GitNexus/gitnexus-claude-plugin/skills/gitnexus-plan/README.md

gitnexus-plan — implementation-ready engineering plans

Generates deep, implementation-ready engineering plans by combining GitNexus repository intelligence, statement-level Program Dependence Graph analysis, and the agent's native targeted source verification.

Invocation

CLI	How to invoke	Adapter file
Claude Code	/gitnexus-plan <task>	.claude/skills/gitnexus-plan/SKILL.md
Codex CLI	Ask: "run gitnexus-plan for " (Codex reads AGENTS.md) — or install the user-level prompt below	AGENTS.md § Engineering planning & execution
Any AGENTS.md-aware agent	Ask it to "read .claude/skills/gitnexus-plan/SKILL.md and follow it for "	AGENTS.md § Engineering planning & execution

/gitnexus-plan Add retry support to the ingestion pipeline
/gitnexus-plan Fix the stale warm-cache invalidation bug in exportedTypeMap
/gitnexus-plan depth:deep impact_depth:3 Migrate the emit phase to streaming COPY

Output: docs/plans/YYYY-MM-DD-gitnexus-plan-<slug>.md — a 13-section plan whose section 11 is a machine-readable implementation context pack that a follow-up agent can consume without re-investigating the repository.

Codex (user-level install)

Codex discovers SKILL.md skills from ~/.agents/skills/ (the same path the other gitnexus-* skills install to). To make this skill auto-discoverable in every Codex session:

cp -r .claude/skills/gitnexus-plan ~/.agents/skills/gitnexus-plan

Codex prompts are user-level only (not repo-shareable). Optionally, for an explicit /gitnexus-plan slash command, also create ~/.codex/prompts/gitnexus-plan.md:

---
description: Implementation-ready engineering plan via GitNexus + PDG + source verification
argument-hint: <task description>
---
Use the gitnexus-plan skill for: $ARGUMENTS

Read `~/.agents/skills/gitnexus-plan/SKILL.md` (if this repo has its own copy at
`.claude/skills/gitnexus-plan/SKILL.md`, prefer that one) and follow its phases in
order, loading its `references/` files at the phases that call for them. Planning
only — never edit code; the only repo file you write is the plan document.

Architecture note: how GitNexus and the agent interact

Three layers, strictly ordered:

1. GitNexus navigates (query → context → impact/trace → cypher last-resort). The graph answers where to look and what is connected: execution flows, callers/callees, blast radius, related tests. Every call must answer a named planning question.
2. PDG constrains (pdg_query controls/flows, impact {mode:"pdg", direction, line} statement slices, explain for taint). The statement-level layers answer what gates and feeds the behavior inside the few functions the change centers on. Results are filtered into a bounded slice (references/pdg-slice.md), never dumped.
3. The agent verifies (targeted line-range reads). Current source is authoritative; graph results are navigation hints until verified. On disagreement: trust source, record the discrepancy, recommend re-indexing.

Token efficiency comes from the context ledger (references/context-ledger.md): every query and read is recorded with the question it answered, and nothing is re-fetched unless the source changed, a contradiction surfaced, or one of the ledger's defined escalations applies (summary→detail drill-down, ambiguity narrowing, a changed parameter answering a new question). The ledger also enforces symbol budgets (5 primary / 20 related by default), and progressive disclosure keeps the big schemas out of context until the phase that needs them.

Files

File	Purpose
SKILL.md	The skill: phases 0–5, hard rules, config, fallback
references/pdg-slice.md	PDG slice construction: tools, inclusion criteria, schema, security/performance modes
references/context-ledger.md	Ledger schema + anti-reread rules
references/plan-template.md	The 13-section plan document template
references/context-pack.md	Implementation context pack schema + stability contract

Requirements and graceful degradation

• Requires a GitNexus index; statement-level sections additionally require the --pdg layers.
• Freshness is a gate, priced by category: full-plan categories (refactor, security, performance, concurrency, architecture) default to freshness: strict — a stale index (or missing PDG layer) is refreshed once with analyze --index-only [--pdg] — run via node .gitnexus/run.cjs when the project has one, else the installed gitnexus CLI (npm install -g gitnexus), else npx gitnexus — before the graph is relied on. Compact-plan categories default to accept (source-weighted, refresh only if a graph claim becomes load-bearing) because the refresh is the largest fixed cost a planning session carries (measured: eval/workflow_bench/). --index-only touches only the .gitnexus store, never repo files. When the repo builds the analyzer from source (like this one: gitnexus/dist), the gate first ensures dist/ is current (npm run build when src is newer) so the refresh doesn't re-index with outdated extraction logic. freshness: accept (or a failed/impractical refresh) plans on the stale graph instead, source-weighted and labelled in the plan header.
• PDG layer still unavailable after that → the plan says so and skips statement-level claims (never reconstructs fake edges).
• No GitNexus at all → fallback mode: targeted grep/read exploration, findings labelled source-derived, with a recommendation to index.

Limitations

• pdg_query is intra-procedural; cross-function flow comes from explain (taint) or impact {mode:"pdg"} inter-procedural reach.
• The skill is planning-only by contract: the only repository file it writes is the plan document, and the only other state it may touch is the .gitnexus index store (freshness refresh) plus the analyzer's dist/ build output (runner build check) — it will not fix what it finds.