openapi: "3.1.0"
info:
  title: Arc Run API
  version: "0.1.0"
  description: HTTP API for managing Arc workflow run executions.

tags:
  - name: Discovery
    description: API discovery and health
  - name: Runs
    description: Run management operations
  - name: Human-in-the-Loop
    description: Questions, answers, and steering for runs
  - name: Run Outputs
    description: Files and verifications produced by runs
  - name: Run Internals
    description: Internal run details (stages, turns, context, configuration)
  - name: Workflows
    description: Workflow definitions and execution
  - name: Verifications
    description: Verification categories and controls
  - name: Usage
    description: Token and cost usage
  - name: Insights
    description: SQL query editor and history
  - name: Sessions
    description: Interactive chat sessions
  - name: Retros
    description: Run retrospectives
  - name: Projects
    description: Project and branch management
  - name: Settings
    description: Platform configuration

security:
  - BearerAuth: []
  - mTLS: []

paths:
  # ── Discovery ────────────────────────────────────────────────────────

  /:
    get:
      operationId: getRoot
      tags: [Discovery]
      summary: API Discovery
      description: Returns discovery URLs for the API.
      security: []
      responses:
        "200":
          description: Discovery URLs
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/RootResponse"

  /health:
    get:
      operationId: getHealth
      tags: [Discovery]
      summary: Health Check
      description: Returns service health status. Used by load balancers and monitoring.
      security: []
      responses:
        "200":
          description: Service is healthy
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/HealthResponse"

  /openapi.json:
    get:
      operationId: getOpenApiSpec
      tags: [Discovery]
      summary: OpenAPI Specification
      description: Returns the OpenAPI spec as JSON.
      security: []
      responses:
        "200":
          description: OpenAPI specification
          content:
            application/json:
              schema:
                type: object

  /user:
    get:
      operationId: getUser
      tags: [Discovery]
      summary: Current User
      description: Returns info about the authenticated user.
      responses:
        "200":
          description: User info
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/UserResponse"
        "401":
          description: Not authenticated
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  # ── Runs ──────────────────────────────────────────────────────────────

  /runs:
    get:
      operationId: listRuns
      tags: [Runs]
      summary: List Runs
      description: Returns a paginated list of runs for the board view, ordered by recency.
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of runs for the board view
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedRunList"
    post:
      operationId: startRun
      tags: [Runs]
      summary: Start Run
      description: Queues a new workflow run from a DOT graph source. The run is created in `queued` status and will be picked up by the scheduler.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/StartRunRequest"
      responses:
        "201":
          description: Run created
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/StartRunResponse"
        "400":
          description: Invalid DOT source
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}:
    get:
      operationId: retrieveRun
      tags: [Runs]
      summary: Retrieve Run
      description: Returns the current status of a run, including error details and queue position if applicable.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Run status
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/RunStatusResponse"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/cancel:
    post:
      operationId: cancelRun
      tags: [Runs]
      summary: Cancel Run
      description: Cancels a running or queued run. Returns 409 if the run has already completed or been cancelled.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Run cancelled
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/CancelRunResponse"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
        "409":
          description: Run is not running
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/graph:
    get:
      operationId: retrieveRunSvg
      tags: [Runs]
      summary: Render SVG
      description: Renders the workflow graph as an SVG image using Graphviz.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: SVG image of the workflow graph
          content:
            image/svg+xml:
              schema:
                type: string
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
        "502":
          description: Graphviz not available
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/checkpoint:
    get:
      operationId: retrieveRunCheckpoint
      tags: [Run Internals]
      summary: Retrieve Run Checkpoint
      description: Returns the latest checkpoint data for a run, or null if no checkpoint has been recorded yet.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Checkpoint data (null if not yet available)
          content:
            application/json:
              schema: {}
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/context:
    get:
      operationId: retrieveRunContext
      tags: [Run Internals]
      summary: Retrieve Run Context
      description: Returns the key-value context map accumulated during the run. Empty if the run has not started.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Context key-value map
          content:
            application/json:
              schema:
                type: object
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/events:
    get:
      operationId: streamRunEvents
      tags: [Runs]
      summary: Stream Run Events
      description: Opens a server-sent event (SSE) stream for real-time run updates. Returns 410 if the stream has been closed.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Server-sent event stream
          content:
            text/event-stream:
              schema:
                type: string
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
        "410":
          description: Event stream closed
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/questions:
    get:
      operationId: listRunQuestions
      tags: [Human-in-the-Loop]
      summary: List Run Questions
      description: Returns pending human-in-the-loop questions for a run. Questions are generated when the workflow needs user input to proceed.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Array of pending questions
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedApiQuestionList"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/questions/{qid}/answer:
    post:
      operationId: submitRunAnswer
      tags: [Human-in-the-Loop]
      summary: Submit Run Answer
      description: Submits an answer to a pending question. The answer can be freeform text or a selected option key, depending on the question type.
      parameters:
        - $ref: "#/components/parameters/RunId"
        - $ref: "#/components/parameters/QuestionId"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SubmitAnswerRequest"
      responses:
        "200":
          description: Answer accepted or rejected
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SubmitAnswerResponse"
        "400":
          description: Invalid option key
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/retro:
    get:
      operationId: retrieveRetro
      tags: [Retros]
      summary: Retrieve Retro
      description: Returns the retrospective analysis for a completed run, or null if the retro has not been generated yet.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Retro data (null if not yet available)
          content:
            application/json:
              schema: {}
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/stages:
    get:
      operationId: listRunStages
      tags: [Run Internals]
      summary: List Run Stages
      description: Returns the ordered list of stages in a run's workflow graph with their current status and timing.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Array of run stages
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedRunStageList"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/stages/{stageId}/turns:
    get:
      operationId: listStageTurns
      tags: [Run Internals]
      summary: List Stage Turns
      description: Returns a paginated list of conversation turns within a specific stage, including system prompts, assistant responses, and tool invocations.
      parameters:
        - $ref: "#/components/parameters/RunId"
        - $ref: "#/components/parameters/StageId"
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of conversation turns
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedStageTurnList"
        "404":
          description: Run or stage not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/compare:
    get:
      operationId: listRunCompare
      tags: [Run Outputs]
      summary: List Run Compare
      description: Returns file-level diffs produced by the run, optionally filtered to a specific checkpoint.
      parameters:
        - $ref: "#/components/parameters/RunId"
        - $ref: "#/components/parameters/CheckpointFilter"
      responses:
        "200":
          description: File changes with checkpoint metadata
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/RunCompare"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/usage:
    get:
      operationId: retrieveRunUsage
      tags: [Run Outputs]
      summary: Retrieve Run Usage
      description: Returns token and cost usage broken down by stage and model for a specific run.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Usage data
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/RunUsage"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/verifications:
    get:
      operationId: listRunVerifications
      tags: [Run Outputs]
      summary: List Run Verifications
      description: Returns verification results for a run, organized by category with individual control statuses.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Array of verification categories with controls
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedRunVerificationList"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/configuration:
    get:
      operationId: retrieveRunConfiguration
      tags: [Run Internals]
      summary: Retrieve Run Configuration
      description: Returns the TOML configuration file content used to launch this run.
      parameters:
        - $ref: "#/components/parameters/RunId"
      responses:
        "200":
          description: Configuration content
          content:
            text/plain:
              schema:
                type: string
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/steer:
    post:
      operationId: steerRun
      tags: [Human-in-the-Loop]
      summary: Steer Run
      description: Sends inline guidance to a running agent, targeting a specific file and line. The guidance is delivered asynchronously.
      parameters:
        - $ref: "#/components/parameters/RunId"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SteerRequest"
      responses:
        "202":
          description: Steering accepted for processing
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SteerRunResponse"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /runs/{id}/preview:
    post:
      operationId: generatePreviewUrl
      tags: [Human-in-the-Loop]
      summary: Preview URL
      description: Generates a time-limited preview URL for a port exposed by the run's sandbox environment.
      parameters:
        - $ref: "#/components/parameters/RunId"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/PreviewUrlRequest"
      responses:
        "200":
          description: Preview URL generated
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PreviewUrlResponse"
        "404":
          description: Run not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  # ── Workflows ─────────────────────────────────────────────────────────

  /workflows:
    get:
      operationId: listWorkflows
      tags: [Workflows]
      summary: List Workflows
      description: Returns a paginated list of workflow definitions available for execution.
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of workflows
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedWorkflowList"

  /workflows/{name}:
    get:
      operationId: retrieveWorkflow
      tags: [Workflows]
      summary: Retrieve Workflow
      description: Returns the full detail of a workflow including its DOT graph, TOML config, and description.
      parameters:
        - $ref: "#/components/parameters/WorkflowName"
      responses:
        "200":
          description: Workflow detail
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/WorkflowDetail"
        "404":
          description: Workflow not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /workflows/{name}/runs:
    get:
      operationId: listWorkflowRuns
      tags: [Workflows]
      summary: List Workflow Runs
      description: Returns a paginated list of runs filtered to a specific workflow.
      parameters:
        - $ref: "#/components/parameters/WorkflowName"
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of runs
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedRunList"
        "404":
          description: Workflow not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
    post:
      operationId: startWorkflowRun
      tags: [Workflows]
      summary: Start Workflow Run
      description: Queues a new run of the specified workflow using its stored DOT graph.
      parameters:
        - $ref: "#/components/parameters/WorkflowName"
      responses:
        "201":
          description: Run created
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/StartRunResponse"
        "404":
          description: Workflow not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  # ── Verifications ─────────────────────────────────────────────────────

  /verifications:
    get:
      operationId: listVerifications
      tags: [Verifications]
      summary: List Verifications
      description: Returns all verification categories with their controls and performance metrics.
      responses:
        "200":
          description: Array of verification categories
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedVerificationCategoryList"

  /verifications/{slug}:
    get:
      operationId: retrieveVerification
      tags: [Verifications]
      summary: Retrieve Verification
      description: Returns detailed information about a specific verification control, including performance data, recent results, and sibling controls in the same category.
      parameters:
        - $ref: "#/components/parameters/VerificationSlug"
      responses:
        "200":
          description: Verification control detail
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/VerificationDetailResponse"
        "404":
          description: Control not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  # ── Retros ────────────────────────────────────────────────────────────

  /retros:
    get:
      operationId: listRetros
      tags: [Retros]
      summary: List Retros
      description: Returns a paginated list of run retrospectives ordered by recency, with smoothness ratings and summary statistics.
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of retros
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedRetroList"

  # ── Sessions ──────────────────────────────────────────────────────────

  /sessions:
    get:
      operationId: listSessions
      tags: [Sessions]
      summary: List Sessions
      description: Returns sessions ordered by recency (newest first).
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of sessions
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedSessionList"
    post:
      operationId: createSession
      tags: [Sessions]
      summary: Create Session
      description: Start a new interactive chat session. The initial user prompt is required; a model may optionally be specified.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/CreateSessionRequest"
      responses:
        "201":
          description: Session created
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/CreateSessionResponse"

  /sessions/{id}:
    get:
      operationId: retrieveSession
      tags: [Sessions]
      summary: Retrieve Session
      description: Returns the full session detail including all conversation turns.
      parameters:
        - $ref: "#/components/parameters/SessionId"
      responses:
        "200":
          description: Session detail
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SessionDetail"
        "404":
          description: Session not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /sessions/{id}/messages:
    post:
      operationId: sendSessionMessage
      tags: [Sessions]
      summary: Send Session Message
      description: Append a user message to an existing session. The server will process it and produce assistant and tool turns asynchronously via the event stream.
      parameters:
        - $ref: "#/components/parameters/SessionId"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SendMessageRequest"
      responses:
        "202":
          description: Message accepted for processing
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SendMessageResponse"
        "404":
          description: Session not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /sessions/{id}/events:
    get:
      operationId: streamSessionEvents
      tags: [Sessions]
      summary: Stream Session Events
      description: |
        Opens a server-sent event (SSE) stream for real-time session updates.

        Each SSE frame includes a sequential numeric `id:` field that supports
        resumption via the `Last-Event-ID` request header.

        The stream emits the following SSE event types:

        - `event: assistant_turn` — data: `AssistantTurn` JSON object
        - `event: tool_turn` — data: `ToolTurn` JSON object
        - `event: done` — data: `{}` (stream complete)
        - `event: error` — data: `{"message": "..."}` (error occurred)

        Each SSE frame has an `id:` line (sequential integer), an `event:` line (the event type),
        and a `data:` line (the JSON payload).
      parameters:
        - $ref: "#/components/parameters/SessionId"
        - name: Last-Event-ID
          in: header
          required: false
          description: >
            SSE reconnection header. When provided, the server resumes the
            stream after the event with this ID. IDs are 0-based sequential
            integers assigned to each emitted SSE frame.
          schema:
            type: string
      responses:
        "200":
          description: Server-sent event stream
          content:
            text/event-stream:
              schema:
                type: string
        "404":
          description: Session not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  # ── Insights ──────────────────────────────────────────────────────────

  /insights/queries:
    get:
      operationId: listSavedQueries
      tags: [Insights]
      summary: List Saved Queries
      description: Returns a paginated list of saved SQL queries for the insights editor.
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of saved queries
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedSavedQueryList"
    post:
      operationId: createSavedQuery
      tags: [Insights]
      summary: Create Saved Query
      description: Saves a new named SQL query for later reuse.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SaveQueryRequest"
      responses:
        "201":
          description: Query saved
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SavedQuery"

  /insights/queries/{id}:
    put:
      operationId: updateSavedQuery
      tags: [Insights]
      summary: Update Saved Query
      description: Replaces the name and SQL of an existing saved query.
      parameters:
        - $ref: "#/components/parameters/InsightQueryId"
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SaveQueryRequest"
      responses:
        "200":
          description: Query updated
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/SavedQuery"
        "404":
          description: Query not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"
    delete:
      operationId: deleteSavedQuery
      tags: [Insights]
      summary: Delete Saved Query
      description: Permanently removes a saved query.
      parameters:
        - $ref: "#/components/parameters/InsightQueryId"
      responses:
        "204":
          description: Query deleted
        "404":
          description: Query not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

  /insights/execute:
    post:
      operationId: executeQuery
      tags: [Insights]
      summary: Execute Query
      description: Executes an ad-hoc SQL query against the analytics database and returns columnar results.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/ExecuteQueryRequest"
      responses:
        "200":
          description: Query results
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ExecuteQueryResponse"

  /insights/history:
    get:
      operationId: listQueryHistory
      tags: [Insights]
      summary: List Query History
      description: Returns a paginated history of recently executed queries with timing and row counts.
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of history entries
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedHistoryEntryList"

  # ── Usage ────────────────────────────────────────────────────────────

  /usage:
    get:
      operationId: getAggregateUsage
      tags: [Usage]
      summary: Aggregate Usage
      description: Returns aggregate token/cost usage across all completed runs since server start.
      responses:
        "200":
          description: Aggregate usage data
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/AggregateUsage"

  # ── Settings ──────────────────────────────────────────────────────────

  /settings:
    get:
      operationId: retrieveServerSettings
      tags: [Settings]
      summary: Retrieve Server Settings
      description: Returns all server settings organized into groups. Each group contains fields with their current values and input types.
      responses:
        "200":
          description: Array of setting groups
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/SettingGroup"

  # ── Projects ──────────────────────────────────────────────────────────

  /projects:
    get:
      operationId: listProjects
      tags: [Projects]
      summary: List Projects
      description: Returns a paginated list of registered projects (repositories).
      parameters:
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of projects
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedProjectList"

  /projects/{id}/branches:
    get:
      operationId: listBranches
      tags: [Projects]
      summary: List Branches
      description: Returns a paginated list of branches for a specific project.
      parameters:
        - $ref: "#/components/parameters/ProjectId"
        - $ref: "#/components/parameters/PageLimit"
        - $ref: "#/components/parameters/PageOffset"
      responses:
        "200":
          description: Paginated list of branches
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/PaginatedBranchList"
        "404":
          description: Project not found
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ErrorResponse"

components:
  securitySchemes:
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: >
        Ed25519-signed JWT issued by arc-web. Required claims: iss ("arc-web"),
        iat, exp. Optional sub claim (GitHub profile URL) identifies the user.
    # OpenAPI 3.1 defines type: mutualTLS, but our parser (openapiv3) only
    # supports 3.0 scheme types. We use apiKey as a placeholder; actual mTLS
    # enforcement happens at the transport layer via client certificates.
    mTLS:
      type: apiKey
      in: header
      name: X-mTLS-Client-CN
      description: >
        Mutual TLS: client certificate signed by the configured CA. Identity
        is extracted from the certificate's Common Name (CN). This scheme is
        enforced at the transport layer, not via an HTTP header.

  parameters:
    RunId:
      name: id
      in: path
      required: true
      description: Unique run identifier (ULID).
      schema:
        type: string
      example: 01JNQVR7M0EJ5GKAT2SC4ERS1Z

    SessionId:
      name: id
      in: path
      required: true
      description: Unique session identifier.
      schema:
        type: string
        format: uuid
      example: a1b2c3d4-e5f6-7890-abcd-ef1234567890

    StageId:
      name: stageId
      in: path
      required: true
      description: Identifier of a stage within a run's workflow graph.
      schema:
        type: string
      example: propose-changes

    QuestionId:
      name: qid
      in: path
      required: true
      description: Unique identifier of a pending question.
      schema:
        type: string
      example: q-001

    WorkflowName:
      name: name
      in: path
      required: true
      description: URL-safe slug identifying a workflow definition.
      schema:
        type: string
      example: fix_build

    VerificationSlug:
      name: slug
      in: path
      required: true
      description: URL-safe slug identifying a verification control.
      schema:
        type: string
      example: motivation

    InsightQueryId:
      name: id
      in: path
      required: true
      description: Unique identifier of a saved query.
      schema:
        type: string
      example: "1"

    ProjectId:
      name: id
      in: path
      required: true
      description: Unique identifier of a project (repository).
      schema:
        type: string
      example: arc-web

    CheckpointFilter:
      name: checkpoint
      in: query
      required: false
      description: Filter file diffs to a specific checkpoint. Defaults to all changes.
      schema:
        type: string
        default: "all"
      example: cp-3

    PageLimit:
      name: page[limit]
      in: query
      required: false
      description: Maximum number of items to return per page.
      schema:
        type: integer
        minimum: 1
        maximum: 100
        default: 20
      example: 20

    PageOffset:
      name: page[offset]
      in: query
      required: false
      description: Number of items to skip before returning results.
      schema:
        type: integer
        minimum: 0
        default: 0
      example: 0

  schemas:
    # ── Pagination ───────────────────────────────────────────────────────

    PaginationMeta:
      description: Pagination metadata included in every paginated response.
      type: object
      required:
        - has_more
      properties:
        has_more:
          type: boolean
          description: Whether additional pages of results are available.
          example: true

    PaginatedRunList:
      description: Paginated list of runs.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/RunListItem"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedWorkflowList:
      description: Paginated list of workflows.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/WorkflowListItem"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedRetroList:
      description: Paginated list of run retrospectives.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/RetroListItem"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedSessionList:
      description: Paginated list of sessions.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/SessionListItem"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedProjectList:
      description: Paginated list of projects.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/Project"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedBranchList:
      description: Paginated list of branches.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/Branch"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedSavedQueryList:
      description: Paginated list of saved queries.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/SavedQuery"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedHistoryEntryList:
      description: Paginated list of query history entries.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/HistoryEntry"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedStageTurnList:
      description: Paginated list of stage turns.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/StageTurn"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedApiQuestionList:
      description: Paginated list of pending questions.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/ApiQuestion"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedRunStageList:
      description: Paginated list of run stages.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/RunStage"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedRunVerificationList:
      description: Paginated list of run verification categories.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/RunVerification"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    PaginatedVerificationCategoryList:
      description: Paginated list of verification categories.
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: array
          items:
            $ref: "#/components/schemas/VerificationCategory"
        meta:
          $ref: "#/components/schemas/PaginationMeta"

    # ── Run Schemas ──────────────────────────────────────────────────────

    RunStatus:
      description: Lifecycle status of a run.
      type: string
      enum:
        - queued
        - starting
        - running
        - completed
        - failed
        - cancelled

    StartRunRequest:
      description: Request body for starting a new run from a DOT graph source.
      type: object
      required:
        - dot_source
      properties:
        dot_source:
          type: string
          description: DOT language source defining the workflow graph.
          example: 'digraph { start [shape=Mdiamond]; exit [shape=Msquare]; start -> exit }'

    StartRunResponse:
      description: Response returned after successfully queuing a new run.
      type: object
      required:
        - id
        - status
        - created_at
      properties:
        id:
          type: string
          description: Unique run identifier (ULID).
          example: 01JNQVR7M0EJ5GKAT2SC4ERS1Z
        status:
          $ref: "#/components/schemas/RunStatus"
        created_at:
          type: string
          format: date-time
          description: Timestamp when the run was created.
          example: "2026-03-06T14:30:00Z"

    RunStatusResponse:
      description: Current status of a run with optional error and queue position.
      type: object
      required:
        - id
        - status
        - created_at
      properties:
        id:
          type: string
          description: Unique run identifier (ULID).
          example: 01JNQVR7M0EJ5GKAT2SC4ERS1Z
        status:
          $ref: "#/components/schemas/RunStatus"
        error:
          type: string
          description: Error message if the run failed.
          example: "Stage 'apply-changes' exceeded maximum retries."
        queue_position:
          type: integer
          description: Position in the queue (1-based). Only present when status is `queued`.
          example: 3
        created_at:
          type: string
          format: date-time
          description: Timestamp when the run was created.
          example: "2026-03-06T14:30:00Z"

    CancelRunResponse:
      description: Response returned after cancelling a run.
      type: object
      required:
        - cancelled
      properties:
        cancelled:
          type: boolean
          description: Whether the cancellation was successful.
          example: true

    SteerRunResponse:
      description: Acknowledgement that the steering guidance was accepted for delivery.
      type: object
      required:
        - accepted
      properties:
        accepted:
          type: boolean
          description: Whether the steering guidance was accepted.
          example: true

    ApiQuestionOption:
      description: A selectable option for a multiple-choice or multi-select question.
      type: object
      required:
        - key
        - label
      properties:
        key:
          type: string
          description: Machine-readable option key used when submitting an answer.
          example: option_a
        label:
          type: string
          description: Human-readable label displayed to the user.
          example: Accept changes

    ApiQuestion:
      description: A pending human-in-the-loop question generated by a workflow stage.
      type: object
      required:
        - id
        - text
        - question_type
        - options
        - allow_freeform
      properties:
        id:
          type: string
          description: Unique question identifier.
          example: q-001
        text:
          type: string
          description: The question text displayed to the user.
          example: Should we proceed with the proposed changes?
        question_type:
          $ref: "#/components/schemas/QuestionType"
        options:
          type: array
          description: Available options for selection-based questions. Empty for freeform questions.
          items:
            $ref: "#/components/schemas/ApiQuestionOption"
        allow_freeform:
          type: boolean
          description: Whether the user may provide freeform text in addition to selecting options.
          example: true

    QuestionType:
      description: The interaction type of a human-in-the-loop question.
      type: string
      enum:
        - yes_no
        - multiple_choice
        - multi_select
        - freeform
        - confirmation

    SubmitAnswerRequest:
      description: Request body for submitting an answer to a pending question.
      type: object
      required:
        - value
      properties:
        value:
          type: string
          description: Freeform answer text.
          example: "Yes, proceed with the changes."
        selected_option_key:
          type: string
          description: Key of the selected option (for multiple-choice questions).
          example: option_a

    SubmitAnswerResponse:
      description: Response indicating whether the submitted answer was accepted.
      type: object
      required:
        - accepted
      properties:
        accepted:
          type: boolean
          description: Whether the answer was accepted. Returns false if the question no longer exists.
          example: true

    ErrorResponseEntry:
      description: A single error entry in an error response.
      type: object
      required:
        - status
        - title
        - detail
      properties:
        status:
          type: string
          description: HTTP status code as a string.
          example: "404"
        title:
          type: string
          description: Short error classification.
          example: Not Found
        detail:
          type: string
          description: Human-readable error description.
          example: Run not found.

    ErrorResponse:
      description: Standard error response containing one or more error entries.
      type: object
      required:
        - errors
      properties:
        errors:
          type: array
          description: List of error entries.
          items:
            $ref: "#/components/schemas/ErrorResponseEntry"

    # ── Run Board Schemas ────────────────────────────────────────────────

    RunListItemStatus:
      description: Board column status for a run in the list view.
      type: string
      enum:
        - working
        - pending
        - review
        - merge

    CheckRunStatus:
      description: Status of a CI check run.
      type: string
      enum:
        - success
        - failure
        - skipped
        - pending
        - queued

    CheckRun:
      description: A CI check run result associated with a run's pull request.
      type: object
      required:
        - name
        - status
      properties:
        name:
          type: string
          description: Name of the CI check.
          example: unit-tests
        status:
          $ref: "#/components/schemas/CheckRunStatus"
        duration_secs:
          type: number
          description: Duration of the check run in seconds.
          example: 154.0

    RunListItem:
      description: Summary of a run shown in the board view.
      type: object
      required:
        - id
        - repo
        - title
        - workflow
        - status
        - created_at
      properties:
        id:
          type: string
          description: Unique run identifier (ULID).
          example: 01JNQVR7M0EJ5GKAT2SC4ERS1Z
        repo:
          type: string
          description: Repository name.
          example: api-server
        title:
          type: string
          description: Human-readable title describing the run's goal.
          example: Add rate limiting to auth endpoints
        workflow:
          type: string
          description: Slug of the workflow that produced this run.
          example: implement
        status:
          $ref: "#/components/schemas/RunListItemStatus"
        number:
          type: integer
          description: Pull request number, if the run has opened a PR.
          example: 889
        additions:
          type: integer
          description: Lines added in the run's diff.
          example: 234
        deletions:
          type: integer
          description: Lines deleted in the run's diff.
          example: 67
        checks:
          type: array
          description: CI check run results for the run's PR.
          items:
            $ref: "#/components/schemas/CheckRun"
        elapsed_secs:
          type: number
          description: Wall-clock time elapsed since the run started, in seconds.
          example: 420.0
        elapsed_warning:
          type: boolean
          description: Whether the elapsed time exceeds the expected threshold.
          example: false
        resources:
          type: string
          description: Compute resources allocated to the run.
          example: 4 CPU / 8 GB
        comments:
          type: integer
          description: Number of review comments on the run's PR.
          example: 4
        question:
          type: string
          description: Text of a pending human-in-the-loop question, if any.
          example: Accept or push for another round?
        sandbox_id:
          type: string
          description: Identifier of the sandbox environment running this run.
          example: sb-a1b2c3d4
        created_at:
          type: string
          format: date-time
          description: Timestamp when the run was created.
          example: "2026-03-06T14:30:00Z"

    # ── Stage / Turn Schemas ─────────────────────────────────────────────

    StageStatus:
      description: Execution status of a workflow stage.
      type: string
      enum:
        - completed
        - running
        - pending
        - failed

    RunStage:
      description: A single stage in a run's workflow graph.
      type: object
      required:
        - id
        - name
        - status
      properties:
        id:
          type: string
          description: Unique stage identifier within the run.
          example: propose-changes
        name:
          type: string
          description: Human-readable stage name.
          example: Propose Changes
        status:
          $ref: "#/components/schemas/StageStatus"
        duration_secs:
          type: number
          description: Time spent in this stage, in seconds.
          example: 154.0
        dot_id:
          type: string
          description: Node identifier in the DOT graph source.
          example: propose

    ToolUse:
      description: A single tool invocation with its input, result, and execution metadata.
      type: object
      required:
        - id
        - tool_name
        - input
        - result
        - is_error
      properties:
        id:
          type: string
          description: Unique identifier for this tool invocation. Enables correlation in parallel tool use.
          example: toolu_01A09q90qw90lq917835lq9
        tool_name:
          type: string
          description: Name of the tool that was invoked.
          example: read_file
        input:
          type: string
          description: JSON-encoded input passed to the tool.
          example: '{ "path": "src/routes/auth.ts" }'
        result:
          type: string
          description: Output returned by the tool. Contains the error message when is_error is true.
          example: 'import { Router } from "express";'
        is_error:
          type: boolean
          description: Whether the tool invocation failed. When true, the result field contains the error message.
          example: false
        duration_ms:
          type: integer
          description: Wall-clock execution time of the tool invocation in milliseconds.
          example: 142

    StageTurn:
      description: A single turn in a stage conversation — a system prompt, assistant response, or tool invocation block.
      discriminator:
        propertyName: kind
        mapping:
          system: "#/components/schemas/SystemStageTurn"
          assistant: "#/components/schemas/AssistantStageTurn"
          tool: "#/components/schemas/ToolStageTurn"
      oneOf:
        - $ref: "#/components/schemas/SystemStageTurn"
        - $ref: "#/components/schemas/AssistantStageTurn"
        - $ref: "#/components/schemas/ToolStageTurn"

    SystemStageTurn:
      description: A system prompt turn that sets the stage's instructions.
      type: object
      required:
        - kind
        - content
      properties:
        kind:
          type: string
          enum: [system]
        content:
          type: string
          description: System prompt text.
          example: You are a drift detection agent. Compare the production and staging environments.
        tools:
          type: array
          description: Tool invocations (always empty for system turns).
          items:
            $ref: "#/components/schemas/ToolUse"

    AssistantStageTurn:
      description: An assistant response turn within a stage.
      type: object
      required:
        - kind
        - content
      properties:
        kind:
          type: string
          enum: [assistant]
        content:
          type: string
          description: Assistant response text.
          example: I'll start by loading the environment configurations for both production and staging.
        tools:
          type: array
          description: Tool invocations (always empty for assistant turns).
          items:
            $ref: "#/components/schemas/ToolUse"

    ToolStageTurn:
      description: A tool invocation turn containing one or more tool calls.
      type: object
      required:
        - kind
        - tools
      properties:
        kind:
          type: string
          enum: [tool]
        content:
          type: string
          description: Optional text content (usually null for tool turns).
        tools:
          type: array
          description: Tool invocations executed in this turn.
          items:
            $ref: "#/components/schemas/ToolUse"

    # ── Compare / Diff Schemas ───────────────────────────────────────────

    FileCheckpoint:
      description: A named checkpoint within a run, used to filter file diffs.
      type: object
      required:
        - id
        - label
      properties:
        id:
          type: string
          description: Checkpoint identifier.
          example: cp-3
        label:
          type: string
          description: Human-readable label for the checkpoint.
          example: "Checkpoint 3 — Review Changes"

    DiffFile:
      description: A file's contents at one side of a diff.
      type: object
      required:
        - name
        - contents
      properties:
        name:
          type: string
          description: File path relative to the repository root.
          example: src/commands/run.ts
        contents:
          type: string
          description: Full file contents. Empty string for newly created or deleted files.
          example: 'import { parseArgs } from "node:util";'

    FileDiff:
      description: A before/after pair showing changes to a single file.
      type: object
      required:
        - old_file
        - new_file
      properties:
        old_file:
          $ref: "#/components/schemas/DiffFile"
        new_file:
          $ref: "#/components/schemas/DiffFile"

    DiffStats:
      description: Aggregate line-change statistics for a diff.
      type: object
      required:
        - additions
        - deletions
      properties:
        additions:
          type: integer
          description: Total lines added.
          example: 567
        deletions:
          type: integer
          description: Total lines deleted.
          example: 234

    RunCompare:
      description: File-level diff output for a run, with checkpoint filtering support.
      type: object
      required:
        - checkpoints
        - files
        - stats
      properties:
        checkpoints:
          type: array
          description: Available checkpoints for filtering.
          items:
            $ref: "#/components/schemas/FileCheckpoint"
        files:
          type: array
          description: File diffs, optionally filtered by checkpoint.
          items:
            $ref: "#/components/schemas/FileDiff"
        stats:
          $ref: "#/components/schemas/DiffStats"

    # ── Usage Schemas ────────────────────────────────────────────────────

    UsageStage:
      description: Token and cost usage for a single stage within a run.
      type: object
      required:
        - stage
        - model
        - input_tokens
        - output_tokens
        - runtime_secs
        - cost
      properties:
        stage:
          type: string
          description: Human-readable stage name.
          example: Propose Changes
        model:
          type: string
          description: Model slug used for this stage.
          example: claude-opus-4-6
        input_tokens:
          type: integer
          description: Number of input tokens consumed.
          example: 28640
        output_tokens:
          type: integer
          description: Number of output tokens generated.
          example: 8750
        runtime_secs:
          type: number
          description: Wall-clock runtime in seconds.
          example: 154.0
        cost:
          type: number
          description: Cost in USD for this stage.
          example: 0.72

    UsageTotals:
      description: Aggregate usage totals across all stages of a run.
      type: object
      required:
        - runtime_secs
        - input_tokens
        - output_tokens
        - cost
      properties:
        runtime_secs:
          type: number
          description: Total wall-clock runtime in seconds.
          example: 389.0
        input_tokens:
          type: integer
          description: Total input tokens consumed.
          example: 71540
        output_tokens:
          type: integer
          description: Total output tokens generated.
          example: 21080
        cost:
          type: number
          description: Total cost in USD.
          example: 2.26

    UsageByModel:
      description: Usage statistics grouped by model.
      type: object
      required:
        - model
        - stages
        - input_tokens
        - output_tokens
        - cost
      properties:
        model:
          type: string
          description: Model slug.
          example: claude-opus-4-6
        stages:
          type: integer
          description: Number of stages that used this model.
          example: 2
        input_tokens:
          type: integer
          description: Total input tokens for this model.
          example: 33780
        output_tokens:
          type: integer
          description: Total output tokens for this model.
          example: 9690
        cost:
          type: number
          description: Total cost in USD for this model.
          example: 1.35

    RunUsage:
      description: Complete usage breakdown for a single run.
      type: object
      required:
        - stages
        - totals
        - by_model
      properties:
        stages:
          type: array
          description: Per-stage usage breakdown.
          items:
            $ref: "#/components/schemas/UsageStage"
        totals:
          $ref: "#/components/schemas/UsageTotals"
        by_model:
          type: array
          description: Usage grouped by model.
          items:
            $ref: "#/components/schemas/UsageByModel"

    AggregateUsage:
      description: Aggregate token and cost usage across all runs since server start.
      type: object
      required:
        - total_runs
        - total_input_tokens
        - total_output_tokens
        - total_cost
        - total_runtime_secs
        - by_model
      properties:
        total_runs:
          type: integer
          description: Total number of completed runs.
          example: 9
        total_input_tokens:
          type: integer
          description: Total input tokens across all runs.
          example: 643860
        total_output_tokens:
          type: integer
          description: Total output tokens across all runs.
          example: 189720
        total_cost:
          type: number
          description: Total cost in USD across all runs.
          example: 20.34
        total_runtime_secs:
          type: number
          description: Total wall-clock runtime in seconds.
          example: 3501.0
        by_model:
          type: array
          description: Usage grouped by model.
          items:
            $ref: "#/components/schemas/UsageByModel"

    # ── Verification Schemas ─────────────────────────────────────────────

    VerificationStatus:
      description: Result status of a verification control evaluation.
      type: string
      enum:
        - pass
        - fail
        - na

    VerificationType:
      description: The evaluation method used by a verification control.
      type: string
      enum:
        - ai
        - automated
        - analysis
        - ai-analysis

    RunVerificationControl:
      description: A verification control result within a run.
      type: object
      required:
        - name
        - description
        - status
      properties:
        name:
          type: string
          description: Human-readable control name.
          example: Motivation
        description:
          type: string
          description: Short description of what the control verifies.
          example: Origin of proposal identified
        type:
          $ref: "#/components/schemas/VerificationType"
        status:
          $ref: "#/components/schemas/VerificationStatus"

    RunVerification:
      description: Verification results for a category within a run.
      type: object
      required:
        - name
        - question
        - status
        - controls
      properties:
        name:
          type: string
          description: Category name.
          example: Traceability
        question:
          type: string
          description: The guiding question for this verification category.
          example: Do we understand what this change is and why we're making it?
        status:
          $ref: "#/components/schemas/VerificationStatus"
        controls:
          type: array
          description: Individual control results within this category.
          items:
            $ref: "#/components/schemas/RunVerificationControl"

    SteerRequest:
      description: Request body for sending inline steering guidance to a running agent.
      type: object
      required:
        - file
        - line
        - guidance
      properties:
        file:
          type: string
          description: File path to target with the guidance.
          example: src/middleware/rate-limit.ts
        line:
          type: integer
          description: Line number in the file to annotate.
          example: 42
        guidance:
          type: string
          description: Guidance text for the agent.
          example: Use a sliding window algorithm instead of fixed window.

    PreviewUrlRequest:
      description: Request body for generating a preview URL from a sandbox port.
      type: object
      required:
        - port
        - expires_in_secs
      properties:
        port:
          type: integer
          description: Port number exposed by the sandbox.
          example: 3000
        expires_in_secs:
          type: integer
          description: Time-to-live for the preview URL in seconds.
          example: 3600

    PreviewUrlResponse:
      description: Response containing the generated preview URL.
      type: object
      required:
        - url
      properties:
        url:
          type: string
          description: Time-limited preview URL.
          example: "https://preview.example.com/sb-a1b2c3d4/3000"

    # ── Workflow Schemas ─────────────────────────────────────────────────

    WorkflowListItem:
      description: Summary of a workflow shown in list views.
      type: object
      required:
        - name
        - slug
        - filename
      properties:
        name:
          type: string
          description: Human-readable workflow name.
          example: Fix Build
        slug:
          type: string
          description: URL-safe slug used in API paths.
          example: fix_build
        filename:
          type: string
          description: DOT graph filename.
          example: fix_build.dot
        last_run:
          type: string
          description: Human-readable relative timestamp of the last run.
          example: 2 hours ago
        schedule:
          type: string
          description: Cron-like schedule expression, if the workflow runs on a schedule.
          example: "0 */6 * * *"
        next_run:
          type: string
          description: Human-readable relative timestamp of the next scheduled run.
          example: in 4 hours

    WorkflowDetail:
      description: Full detail of a workflow definition including graph and configuration.
      type: object
      required:
        - title
        - slug
        - filename
        - description
        - config
        - graph
      properties:
        title:
          type: string
          description: Human-readable workflow title.
          example: Fix Build
        slug:
          type: string
          description: URL-safe slug used in API paths.
          example: fix_build
        filename:
          type: string
          description: DOT graph filename.
          example: fix_build.dot
        description:
          type: string
          description: Prose description of what the workflow does.
          example: Automatically diagnoses and fixes CI build failures.
        config:
          type: string
          description: TOML configuration content for the workflow.
          example: "version = 1\ngoal = \"Fix CI build failures\""
        graph:
          type: string
          description: DOT language source defining the workflow graph.
          example: "digraph fix_build { rankdir=LR; start -> diagnose -> fix -> validate }"

    # ── Verification Detail Schemas ──────────────────────────────────────

    EvaluationResult:
      description: Outcome of a single verification evaluation.
      type: string
      enum:
        - pass
        - fail
        - skip

    VerificationMode:
      description: Operational mode of a verification control.
      type: string
      enum:
        - active
        - evaluate
        - disabled

    VerificationControl:
      description: A verification control within a category, with performance metrics.
      type: object
      required:
        - name
        - slug
        - description
      properties:
        name:
          type: string
          description: Human-readable control name.
          example: Motivation
        slug:
          type: string
          description: URL-safe slug for API lookups.
          example: motivation
        description:
          type: string
          description: Short description of what the control verifies.
          example: Origin of proposal identified
        type:
          $ref: "#/components/schemas/VerificationType"
        mode:
          $ref: "#/components/schemas/VerificationMode"
        f1:
          type: number
          description: F1 score of the control's AI evaluator.
          example: 0.87
        pass_at_1:
          type: number
          description: Pass@1 rate — probability of passing on the first evaluation.
          example: 0.82
        evaluations:
          type: array
          description: Recent evaluation results (newest first).
          items:
            $ref: "#/components/schemas/EvaluationResult"

    VerificationCategory:
      description: A group of related verification controls.
      type: object
      required:
        - name
        - question
        - controls
      properties:
        name:
          type: string
          description: Category name.
          example: Traceability
        question:
          type: string
          description: Guiding question for the category.
          example: Do we understand what this change is and why we're making it?
        controls:
          type: array
          description: Verification controls in this category.
          items:
            $ref: "#/components/schemas/VerificationControl"

    ControlInfo:
      description: Core metadata about a verification control.
      type: object
      required:
        - name
        - slug
        - description
        - category
      properties:
        name:
          type: string
          description: Human-readable control name.
          example: Motivation
        slug:
          type: string
          description: URL-safe slug.
          example: motivation
        description:
          type: string
          description: Short description of what the control verifies.
          example: Origin of proposal identified
        type:
          $ref: "#/components/schemas/VerificationType"
        category:
          type: string
          description: Name of the category this control belongs to.
          example: Traceability

    ControlPerformance:
      description: Performance metrics for a verification control.
      type: object
      required:
        - mode
        - evaluations
      properties:
        mode:
          $ref: "#/components/schemas/VerificationMode"
        f1:
          type: number
          description: F1 score of the control's AI evaluator.
          example: 0.87
        pass_at_1:
          type: number
          description: Pass@1 rate.
          example: 0.82
        evaluations:
          type: array
          description: Recent evaluation results (newest first).
          items:
            $ref: "#/components/schemas/EvaluationResult"

    ControlDetail:
      description: Detailed information about a verification control including checks and examples.
      type: object
      required:
        - description
        - checks
        - pass_example
        - fail_example
      properties:
        description:
          type: string
          description: Detailed prose description of the control's purpose and rationale.
          example: Verifies that every change traces back to a clear origin.
        checks:
          type: array
          description: Specific checks performed by this control.
          items:
            type: string
          example: ["PR body explains why the change is needed", "Commit messages reference a ticket"]
        pass_example:
          type: string
          description: Example scenario where the control passes.
          example: PR links to JIRA-1234 and explains the user-facing pain point.
        fail_example:
          type: string
          description: Example scenario where the control fails.
          example: PR description is empty or says only 'fix stuff'.

    RecentControlResult:
      description: Result of a recent verification control evaluation for a specific run.
      type: object
      required:
        - run_id
        - run_title
        - workflow
        - result
        - timestamp
      properties:
        run_id:
          type: string
          description: Identifier of the run that was evaluated.
          example: run-047
        run_title:
          type: string
          description: Title of the evaluated run.
          example: "PR #312 — Add OAuth2 PKCE flow"
        workflow:
          type: string
          description: Workflow that produced the run.
          example: code_review
        result:
          $ref: "#/components/schemas/VerificationStatus"
        timestamp:
          type: string
          description: Human-readable relative timestamp of the evaluation.
          example: 2h ago

    SiblingControl:
      description: Summary of a sibling verification control in the same category.
      type: object
      required:
        - name
        - slug
      properties:
        name:
          type: string
          description: Human-readable control name.
          example: Specifications
        slug:
          type: string
          description: URL-safe slug.
          example: specifications
        type:
          $ref: "#/components/schemas/VerificationType"
        mode:
          $ref: "#/components/schemas/VerificationMode"

    VerificationDetailResponse:
      description: Complete detail view of a verification control with performance, examples, and recent results.
      type: object
      required:
        - control
        - performance
        - control_detail
        - recent_results
        - siblings
      properties:
        control:
          $ref: "#/components/schemas/ControlInfo"
        performance:
          $ref: "#/components/schemas/ControlPerformance"
        control_detail:
          $ref: "#/components/schemas/ControlDetail"
        recent_results:
          type: array
          description: Recent evaluation results across runs.
          items:
            $ref: "#/components/schemas/RecentControlResult"
        siblings:
          type: array
          description: Other controls in the same category.
          items:
            $ref: "#/components/schemas/SiblingControl"

    # ── Retro Schemas ────────────────────────────────────────────────────

    SmoothnessRating:
      description: Qualitative assessment of how smoothly a run executed.
      type: string
      enum:
        - effortless
        - smooth
        - bumpy
        - struggled
        - failed

    RetroStats:
      description: Summary statistics for a run retrospective.
      type: object
      required:
        - total_duration_ms
        - total_retries
        - files_touched
        - stages_completed
        - stages_failed
      properties:
        total_duration_ms:
          type: integer
          description: Total run duration in milliseconds.
          example: 389000
        total_cost:
          type: number
          description: Total cost in USD.
          example: 2.78
        total_retries:
          type: integer
          description: Total number of retries across all stages.
          example: 0
        files_touched:
          type: array
          description: List of files modified during the run.
          items:
            type: string
          example: ["src/middleware/rate-limit.ts", "src/routes/auth.ts"]
        stages_completed:
          type: integer
          description: Number of stages that completed successfully.
          example: 4
        stages_failed:
          type: integer
          description: Number of stages that failed.
          example: 0

    RetroListItem:
      description: Summary of a run retrospective shown in list views.
      type: object
      required:
        - run_id
        - workflow_name
        - goal
        - timestamp
        - stats
        - friction_point_count
      properties:
        run_id:
          type: string
          description: Identifier of the run this retro belongs to.
          example: run-1
        workflow_name:
          type: string
          description: Name of the workflow that produced the run.
          example: implement
        goal:
          type: string
          description: The run's goal.
          example: Add rate limiting to auth endpoints
        timestamp:
          type: string
          format: date-time
          description: Timestamp when the retro was generated.
          example: "2026-02-28T14:32:00Z"
        smoothness:
          $ref: "#/components/schemas/SmoothnessRating"
        stats:
          $ref: "#/components/schemas/RetroStats"
        friction_point_count:
          type: integer
          description: Number of friction points identified in the retro.
          example: 0

    # ── Session Schemas ──────────────────────────────────────────────────

    SessionListItem:
      description: Summary of a session shown in list views.
      type: object
      required:
        - id
        - title
        - model
        - last_message_preview
        - created_at
        - updated_at
      properties:
        id:
          type: string
          format: uuid
          description: Unique session identifier.
          example: a1b2c3d4-e5f6-7890-abcd-ef1234567890
        title:
          type: string
          description: Short title summarizing the session topic.
          example: Add rate limiting to auth endpoints
        model:
          type: string
          description: The LLM model used for this session.
          example: claude-opus-4-6
        last_message_preview:
          type: string
          description: Truncated snippet of the most recent turn's content.
          example: "Done. I've created the rate limiter and wired it up..."
        created_at:
          type: string
          format: date-time
          description: Timestamp when the session was created.
          example: "2026-03-06T14:30:00Z"
        updated_at:
          type: string
          format: date-time
          description: Timestamp when the session was last updated (e.g. new turn added).
          example: "2026-03-06T15:45:00Z"


    SessionTurn:
      description: A single turn in a session conversation — a user message, assistant response, or tool invocation block.
      discriminator:
        propertyName: kind
        mapping:
          user: "#/components/schemas/UserTurn"
          assistant: "#/components/schemas/AssistantTurn"
          tool: "#/components/schemas/ToolTurn"
      oneOf:
        - $ref: "#/components/schemas/UserTurn"
        - $ref: "#/components/schemas/AssistantTurn"
        - $ref: "#/components/schemas/ToolTurn"

    UserTurn:
      description: A user message turn.
      type: object
      required:
        - kind
        - content
        - created_at
      properties:
        kind:
          type: string
          enum: [user]
        content:
          type: string
          description: Text content of the user message.
          example: Add rate limiting to the auth endpoints using a sliding window approach with Redis.
        created_at:
          type: string
          format: date-time
          description: Timestamp when the turn was created.
          example: "2026-02-28T10:00:00Z"

    AssistantTurn:
      description: An assistant response turn.
      type: object
      required:
        - kind
        - content
        - created_at
      properties:
        kind:
          type: string
          enum: [assistant]
        content:
          type: string
          description: Text content of the assistant response.
          example: I'll implement sliding window rate limiting using Redis.
        created_at:
          type: string
          format: date-time
          description: Timestamp when the turn was created.
          example: "2026-02-28T10:01:00Z"

    ToolTurn:
      description: A tool invocation turn.
      type: object
      required:
        - kind
        - tools
        - created_at
      properties:
        kind:
          type: string
          enum: [tool]
        tools:
          type: array
          description: Tool invocations for this turn.
          items:
            $ref: "#/components/schemas/ToolUse"
        created_at:
          type: string
          format: date-time
          description: Timestamp when the turn was created.
          example: "2026-02-28T10:01:05Z"

    SessionDetail:
      description: Full session record including metadata and the complete conversation history.
      type: object
      required:
        - id
        - title
        - model
        - created_at
        - updated_at
        - turns
      properties:
        id:
          type: string
          format: uuid
          description: Unique session identifier.
          example: a1b2c3d4-e5f6-7890-abcd-ef1234567890
        title:
          type: string
          description: Short title summarizing the session topic.
          example: Add rate limiting to auth endpoints
        model:
          type: string
          description: The LLM model used for this session.
          example: claude-opus-4-6
        created_at:
          type: string
          format: date-time
          description: Timestamp when the session was created.
          example: "2026-03-06T14:30:00Z"
        updated_at:
          type: string
          format: date-time
          description: Timestamp when the session was last updated (e.g. new turn added).
          example: "2026-03-06T15:45:00Z"
        turns:
          type: array
          description: Ordered list of conversation turns.
          items:
            $ref: "#/components/schemas/SessionTurn"

    CreateSessionRequest:
      description: Request body for starting a new session.
      type: object
      required:
        - content
      properties:
        content:
          type: string
          description: The initial user message to start the session.
          example: Add rate limiting to the auth endpoints using a sliding window approach with Redis, 10 requests per minute per IP.
        model:
          type: string
          description: LLM model to use. If omitted, the server default is used.
          example: claude-opus-4-6

    CreateSessionResponse:
      description: Response returned after successfully creating a session.
      type: object
      required:
        - id
        - title
        - model
        - created_at
        - updated_at
      properties:
        id:
          type: string
          format: uuid
          description: Unique identifier for the newly created session.
          example: a1b2c3d4-e5f6-7890-abcd-ef1234567890
        title:
          type: string
          description: Server-generated title for the session.
          example: Add rate limiting to auth endpoints
        model:
          type: string
          description: The resolved LLM model for this session (may be the server default).
          example: claude-opus-4-6
        created_at:
          type: string
          format: date-time
          description: Timestamp when the session was created.
          example: "2026-03-06T16:00:00Z"
        updated_at:
          type: string
          format: date-time
          description: Timestamp when the session was last updated (equal to created_at at creation time).
          example: "2026-03-06T16:00:00Z"

    SendMessageRequest:
      description: Request body for sending a follow-up message in an existing session.
      type: object
      required:
        - content
      properties:
        content:
          type: string
          description: The user message text.
          example: Can you also add a bypass for internal health-check IPs?

    SendMessageResponse:
      description: Acknowledgement that the message was accepted for asynchronous processing.
      type: object
      required:
        - accepted
      properties:
        accepted:
          type: boolean
          description: Whether the message was accepted for processing.
          example: true

    # ── Insights Schemas ─────────────────────────────────────────────────

    SavedQuery:
      description: A saved SQL query for the insights editor.
      type: object
      required:
        - id
        - name
        - sql
        - created_at
      properties:
        id:
          type: string
          description: Unique query identifier.
          example: "1"
        name:
          type: string
          description: Human-readable query name.
          example: Run duration by workflow
        sql:
          type: string
          description: SQL query text.
          example: "SELECT workflow_name, AVG(duration_seconds) FROM runs GROUP BY 1"
        created_at:
          type: string
          format: date-time
          description: Timestamp when the query was saved.
          example: "2026-03-01T10:00:00Z"
        updated_at:
          type: string
          format: date-time
          description: Timestamp when the query was last modified.
          example: "2026-03-05T14:30:00Z"

    SaveQueryRequest:
      description: Request body for creating or updating a saved query.
      type: object
      required:
        - name
        - sql
      properties:
        name:
          type: string
          description: Human-readable query name.
          example: Run duration by workflow
        sql:
          type: string
          description: SQL query text.
          example: "SELECT workflow_name, AVG(duration_seconds) FROM runs GROUP BY 1"

    ExecuteQueryRequest:
      description: Request body for executing an ad-hoc SQL query.
      type: object
      required:
        - sql
      properties:
        sql:
          type: string
          description: SQL query to execute.
          example: "SELECT workflow_name, COUNT(*) FROM runs GROUP BY 1"

    ExecuteQueryResponse:
      description: Columnar result set from an executed query.
      type: object
      required:
        - columns
        - rows
        - elapsed
        - row_count
      properties:
        columns:
          type: array
          description: Column names in the result set.
          items:
            type: string
          example: ["workflow_name", "count"]
        rows:
          type: array
          description: Result rows, each an array of values matching the column order.
          items:
            type: array
            items: {}
        elapsed:
          type: number
          description: Query execution time in seconds.
          example: 0.342
        row_count:
          type: integer
          description: Number of rows returned.
          example: 3

    HistoryEntry:
      description: A previously executed query in the history log.
      type: object
      required:
        - id
        - sql
        - timestamp
        - elapsed
        - row_count
      properties:
        id:
          type: string
          description: Unique history entry identifier.
          example: h1
        sql:
          type: string
          description: SQL query that was executed.
          example: "SELECT workflow_name, COUNT(*) FROM runs GROUP BY 1"
        timestamp:
          type: string
          description: Human-readable relative timestamp of execution.
          example: 2 min ago
        elapsed:
          type: number
          description: Query execution time in seconds.
          example: 0.342
        row_count:
          type: integer
          description: Number of rows returned.
          example: 6

    # ── Settings Schemas ─────────────────────────────────────────────────

    SettingFieldType:
      description: Input type for a setting field.
      type: string
      enum:
        - text
        - select
        - toggle

    SettingField:
      description: A single configurable setting within a group.
      type: object
      required:
        - key
        - label
        - value
        - type
      properties:
        key:
          type: string
          description: Machine-readable setting key.
          example: org_name
        label:
          type: string
          description: Human-readable label displayed in the UI.
          example: Organization name
        value:
          type: string
          description: Current value of the setting.
          example: Acme Corp
        type:
          $ref: "#/components/schemas/SettingFieldType"
        options:
          type: array
          description: Available options for select-type fields.
          items:
            type: string
          example: ["America/New_York", "UTC", "Europe/London"]
        description:
          type: string
          description: Additional help text for the setting.
          example: Comma-separated CIDRs. Leave empty to allow all.

    SettingGroup:
      description: A logical group of related settings.
      type: object
      required:
        - id
        - name
        - description
        - fields
      properties:
        id:
          type: string
          description: Machine-readable group identifier.
          example: general
        name:
          type: string
          description: Human-readable group name.
          example: General
        description:
          type: string
          description: Prose description of the settings group.
          example: Core platform settings and defaults.
        fields:
          type: array
          description: Settings within this group.
          items:
            $ref: "#/components/schemas/SettingField"

    # ── Project Schemas ──────────────────────────────────────────────────

    Project:
      description: A registered project (repository).
      type: object
      required:
        - id
        - name
      properties:
        id:
          type: string
          description: Unique project identifier.
          example: arc-web
        name:
          type: string
          description: Human-readable project name.
          example: arc-web

    Branch:
      description: A branch within a project.
      type: object
      required:
        - id
        - name
      properties:
        id:
          type: string
          description: Branch identifier.
          example: main
        name:
          type: string
          description: Branch name.
          example: main

    # ── Discovery Schemas ────────────────────────────────────────────────

    RootResponseUrls:
      description: Collection of API discovery URLs.
      type: object
      required:
        - openapi_url
        - current_user_url
        - health_url
      properties:
        openapi_url:
          type: string
          description: URL of the OpenAPI JSON specification.
          example: /openapi.json
        current_user_url:
          type: string
          description: URL of the current user endpoint.
          example: /user
        health_url:
          type: string
          description: URL of the health check endpoint.
          example: /health

    RootResponse:
      description: API discovery response with navigation URLs.
      type: object
      required:
        - urls
      properties:
        urls:
          $ref: "#/components/schemas/RootResponseUrls"

    HealthResponse:
      description: Service health check response.
      type: object
      required:
        - status
      properties:
        status:
          type: string
          description: Health status indicator.
          example: ok

    UserResponse:
      description: Information about the authenticated user.
      type: object
      required:
        - login
      properties:
        login:
          type: string
          description: User's login identifier (e.g. GitHub username).
          example: octocat