diff --git a/run.json b/run.json
index d2dfbe2be..d8116a487 100644
--- a/run.json
+++ b/run.json
@@ -516,7 +516,7 @@
     "kind": "running"
   },
   "status_updated_at": "2026-05-22T02:05:04.152753Z",
-  "last_event_at": "2026-05-22T02:07:25.170351Z",
+  "last_event_at": "2026-05-22T02:14:14.430432Z",
   "pending_control": null,
   "checkpoints": [
     {
@@ -683,9 +683,9 @@
       }
     },
     {
-      "seq": 0,
+      "seq": 47,
       "checkpoint": {
-        "timestamp": "2026-05-22T02:09:41.310671Z",
+        "timestamp": "2026-05-22T02:09:45.568058Z",
         "current_node": "preflight_lint",
         "completed_nodes": [
           "start",
@@ -694,15 +694,101 @@
           "preflight_lint"
         ],
         "node_retries": {},
+        "context_values": {
+          "graph.goal": "# Plan: Compute LLM cost on-read for in-flight stages\n\n## Context\n\nOn the run billing page (`/runs/{id}/billing`), an active stage shows token\nusage but no dollar cost — cost renders as `—` until the stage completes.\n\nRoot cause: while a stage runs, `AgentMessage` events carry usage built by\n`billed_token_counts_from_llm` (`fabro-workflow/src/outcome.rs:43`), which\nhard-codes `total_usd_micros: None`. Dollar cost is only computed by\n`billed_model_usage_from_llm` (`outcome.rs:14`) — which needs the pricing\n`Catalog` — and that runs only on `StageCompleted`/`PromptCompleted`/`StageFailed`.\nSo an in-flight stage's `StageProjection.usage.total_usd_micros` stays `None`.\n\nFix: price stages whose cost is `None` when the billing rollup is built for a\nread request, using the model + token counts already in the projection. The\nwire contract is unchanged (`total_usd_micros` is already nullable everywhere)\nand the frontend already renders whatever value comes back — no UI change.\n\n## Decisions\n\n- **Price any stage with `total_usd_micros == None`**, not just in-flight ones.\n  Completed stages with unpriceable providers (`BillingPolicy::None`) return\n  `None` again — harmless; no need to thread `StageState`.\n- **No \"estimated\" label.** Cost-so-far is exact for tokens consumed so far,\n  matching the already-unlabeled live token counts and ticking runtime.\n- **Aggregate billing stays finalized-only.** The `BillingAccumulator` call\n  sites pass `None` so a run's running estimate is never folded into org-wide\n  totals (avoids double-count when the run later finalizes).\n- Per-stage rows, `totals`, and `by_model` are all priced from the same source\n  so the billing page stays internally consistent.\n\n## Changes\n\n### 1. `lib/crates/fabro-model/src/billing.rs`\n\n- Add `BilledTokenCounts::token_counts(&self) -> TokenCounts` — drops\n  `total_tokens`/`total_usd_micros`, keeps the five disjoint buckets.\n- Add `Catalog::price_tokens(&self, model: &ModelRef, tokens: &TokenCounts) -> Option<i64>`\n  next to `pricing_for`/`billing_facts_for`. Body mirrors the cost lines of\n  `billed_model_usage_from_llm`: build `ModelBillingFacts` via\n  `billing_facts_for`, assemble `ModelBillingInput { ModelUsage { model, tokens }, facts }`,\n  then `pricing_for(model).and_then(|p| p.bill(&input)).map(|a| a.0)`. Returns\n  `None` when the provider has no billing policy.\n\n### 2. `lib/crates/fabro-workflow/src/billing_rollup.rs`\n\n- Change signature to\n  `billing_rollup_from_projection(projection: &RunProjection, catalog: Option<&Catalog>)`.\n- Add a module-private helper `stage_usage_with_cost(catalog, stage) -> BilledTokenCounts`:\n  clone `stage.usage`; if `total_usd_micros.is_none()` and both `catalog` and\n  `stage.model` are present, set it via `catalog.price_tokens(model, &usage.token_counts())`.\n- In the loop, compute `priced` once per stage and use it in place of\n  `&stage.usage` for the `is_zero` check, `row.billing.add_counts`,\n  `totals.add_counts`, and `model_entry.billing.add_counts`.\n- Update the existing tests to pass `None`; add one new test: an in-flight\n  stage (no `completion`, non-zero `usage` with `total_usd_micros: None`, a\n  builtin `model`) yields `Some(..)` cost on the stage row and in `totals` when\n  called with `Some(Catalog::builtin())`.\n\n### 3. Call sites of `billing_rollup_from_projection`\n\n- `lib/crates/fabro-server/src/server/handler/billing.rs:82` — bind\n  `let catalog = state.catalog();` (returns `Arc<Catalog>`) and pass\n  `Some(&catalog)`.\n- `lib/crates/fabro-server/src/server.rs` (2 aggregate-billing sites) — pass `None`.\n- `lib/crates/fabro-workflow/src/pipeline/finalize.rs` (4 sites) — pass `None`\n  (stages already priced at completion; pricing would be a no-op anyway).\n\nNo changes to `fabro-api.yaml`, the generated clients, or `apps/fabro-web`.\n\n## Out of scope / known limitation\n\nIn-flight **prompt** stages have no `model` until `PromptCompleted` (only\n`AgentMessage` sets `stage.model` mid-run), so they still show `—` while\nrunning. Acceptable: prompt stages are a single short LLM call. The bug report\nconcerns agent stages, where `model` is available.\n\n## Verification\n\n- `cargo nextest run -p fabro-workflow billing_rollup` — new + updated unit tests pass.\n- `cargo nextest run -p fabro-server billing` — handler conformance still passes.\n- `cargo build --workspace` and `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`.\n- Manual: `fabro server start` + `cd apps/fabro-web && bun run dev`, start a\n  workflow with an agent stage, open `/runs/{id}/billing` mid-run — the active\n  stage row and totals show a non-`—` dollar amount that grows with tokens.\n",
+          "graph.model_stylesheet": "\n            * { model: claude-opus-4-7; }\n        ",
+          "internal.retry_count.start": 0,
+          "internal.fidelity": "compact",
+          "internal.retry_count.preflight_compile": 0,
+          "internal.thread_id": "preflight_compile",
+          "failure_signature": "",
+          "internal.work_dir": "/home/daytona/workspace/fabro",
+          "thread.start.current_node": "toolchain",
+          "command.output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126",
+          "internal.retry_count.toolchain": 0,
+          "graph.rankdir": "LR",
+          "internal.retry_count.preflight_lint": 0,
+          "internal.node_visit_count": 1,
+          "failure_class": "",
+          "outcome": "succeeded",
+          "internal.run_id": "01KS6PV4WMWSVNJ3F6Z8K04MV9",
+          "thread.preflight_compile.current_node": "preflight_lint",
+          "current_node": "preflight_lint",
+          "thread.toolchain.current_node": "preflight_compile"
+        },
+        "node_outcomes": {
+          "preflight_compile": {
+            "status": "succeeded",
+            "context_updates": {
+              "command.output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126"
+            },
+            "notes": "Script completed: cargo check -q --workspace 2>&1",
+            "usage": null
+          },
+          "start": {
+            "status": "succeeded",
+            "usage": null
+          },
+          "preflight_lint": {
+            "status": "succeeded",
+            "context_updates": {
+              "command.output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126"
+            },
+            "notes": "Script completed: cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1",
+            "usage": null
+          },
+          "toolchain": {
+            "status": "succeeded",
+            "context_updates": {
+              "command.output": "blob://sha256/fc14b2ba2d770e5cd3169df7a29525c962adfc4cfa3097b9098c63ebd61a748c"
+            },
+            "notes": "Script completed: command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1",
+            "usage": null
+          }
+        },
+        "next_node_id": "implement",
+        "git_commit_sha": "bbb23af87ed5f7ab6c8d5271e51af155a2446582",
+        "node_visits": {
+          "toolchain": 1,
+          "start": 1,
+          "preflight_compile": 1,
+          "preflight_lint": 1
+        }
+      },
+      "diff": {
+        "summary": {
+          "files_changed": 0,
+          "additions": 0,
+          "deletions": 0
+        }
+      }
+    },
+    {
+      "seq": 0,
+      "checkpoint": {
+        "timestamp": "2026-05-22T02:14:14.489264Z",
+        "current_node": "implement",
+        "completed_nodes": [
+          "start",
+          "toolchain",
+          "preflight_compile",
+          "preflight_lint",
+          "implement"
+        ],
+        "node_retries": {},
         "context_values": {
           "command.output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126",
           "internal.node_visit_count": 1,
+          "thread.preflight_lint.current_node": "implement",
           "graph.rankdir": "LR",
           "internal.retry_count.start": 0,
           "thread.toolchain.current_node": "preflight_compile",
+          "last_response": "All verification steps pass. Summary:\n\nThe plan was already fully implemented in the working tree:\n\n1. **`lib/crates/fabro-model/src/billing.rs`** — `BilledTokenCounts::token_counts()` and `Catalog:",
           "failure_signature": "",
           "thread.preflight_compile.current_node": "preflight_lint",
           "internal.retry_count.preflight_lint": 0,
+          "last_stage": "implement",
+          "internal.retry_count.implement": 0,
           "failure_class": "",
           "graph.goal": "# Plan: Compute LLM cost on-read for in-flight stages\n\n## Context\n\nOn the run billing page (`/runs/{id}/billing`), an active stage shows token\nusage but no dollar cost — cost renders as `—` until the stage completes.\n\nRoot cause: while a stage runs, `AgentMessage` events carry usage built by\n`billed_token_counts_from_llm` (`fabro-workflow/src/outcome.rs:43`), which\nhard-codes `total_usd_micros: None`. Dollar cost is only computed by\n`billed_model_usage_from_llm` (`outcome.rs:14`) — which needs the pricing\n`Catalog` — and that runs only on `StageCompleted`/`PromptCompleted`/`StageFailed`.\nSo an in-flight stage's `StageProjection.usage.total_usd_micros` stays `None`.\n\nFix: price stages whose cost is `None` when the billing rollup is built for a\nread request, using the model + token counts already in the projection. The\nwire contract is unchanged (`total_usd_micros` is already nullable everywhere)\nand the frontend already renders whatever value comes back — no UI change.\n\n## Decisions\n\n- **Price any stage with `total_usd_micros == None`**, not just in-flight ones.\n  Completed stages with unpriceable providers (`BillingPolicy::None`) return\n  `None` again — harmless; no need to thread `StageState`.\n- **No \"estimated\" label.** Cost-so-far is exact for tokens consumed so far,\n  matching the already-unlabeled live token counts and ticking runtime.\n- **Aggregate billing stays finalized-only.** The `BillingAccumulator` call\n  sites pass `None` so a run's running estimate is never folded into org-wide\n  totals (avoids double-count when the run later finalizes).\n- Per-stage rows, `totals`, and `by_model` are all priced from the same source\n  so the billing page stays internally consistent.\n\n## Changes\n\n### 1. `lib/crates/fabro-model/src/billing.rs`\n\n- Add `BilledTokenCounts::token_counts(&self) -> TokenCounts` — drops\n  `total_tokens`/`total_usd_micros`, keeps the five disjoint buckets.\n- Add `Catalog::price_tokens(&self, model: &ModelRef, tokens: &TokenCounts) -> Option<i64>`\n  next to `pricing_for`/`billing_facts_for`. Body mirrors the cost lines of\n  `billed_model_usage_from_llm`: build `ModelBillingFacts` via\n  `billing_facts_for`, assemble `ModelBillingInput { ModelUsage { model, tokens }, facts }`,\n  then `pricing_for(model).and_then(|p| p.bill(&input)).map(|a| a.0)`. Returns\n  `None` when the provider has no billing policy.\n\n### 2. `lib/crates/fabro-workflow/src/billing_rollup.rs`\n\n- Change signature to\n  `billing_rollup_from_projection(projection: &RunProjection, catalog: Option<&Catalog>)`.\n- Add a module-private helper `stage_usage_with_cost(catalog, stage) -> BilledTokenCounts`:\n  clone `stage.usage`; if `total_usd_micros.is_none()` and both `catalog` and\n  `stage.model` are present, set it via `catalog.price_tokens(model, &usage.token_counts())`.\n- In the loop, compute `priced` once per stage and use it in place of\n  `&stage.usage` for the `is_zero` check, `row.billing.add_counts`,\n  `totals.add_counts`, and `model_entry.billing.add_counts`.\n- Update the existing tests to pass `None`; add one new test: an in-flight\n  stage (no `completion`, non-zero `usage` with `total_usd_micros: None`, a\n  builtin `model`) yields `Some(..)` cost on the stage row and in `totals` when\n  called with `Some(Catalog::builtin())`.\n\n### 3. Call sites of `billing_rollup_from_projection`\n\n- `lib/crates/fabro-server/src/server/handler/billing.rs:82` — bind\n  `let catalog = state.catalog();` (returns `Arc<Catalog>`) and pass\n  `Some(&catalog)`.\n- `lib/crates/fabro-server/src/server.rs` (2 aggregate-billing sites) — pass `None`.\n- `lib/crates/fabro-workflow/src/pipeline/finalize.rs` (4 sites) — pass `None`\n  (stages already priced at completion; pricing would be a no-op anyway).\n\nNo changes to `fabro-api.yaml`, the generated clients, or `apps/fabro-web`.\n\n## Out of scope / known limitation\n\nIn-flight **prompt** stages have no `model` until `PromptCompleted` (only\n`AgentMessage` sets `stage.model` mid-run), so they still show `—` while\nrunning. Acceptable: prompt stages are a single short LLM call. The bug report\nconcerns agent stages, where `model` is available.\n\n## Verification\n\n- `cargo nextest run -p fabro-workflow billing_rollup` — new + updated unit tests pass.\n- `cargo nextest run -p fabro-server billing` — handler conformance still passes.\n- `cargo build --workspace` and `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`.\n- Manual: `fabro server start` + `cd apps/fabro-web && bun run dev`, start a\n  workflow with an agent stage, open `/runs/{id}/billing` mid-run — the active\n  stage row and totals show a non-`—` dollar amount that grows with tokens.\n",
           "internal.retry_count.toolchain": 0,
@@ -711,9 +797,10 @@
           "thread.start.current_node": "toolchain",
           "internal.work_dir": "/home/daytona/workspace/fabro",
           "graph.model_stylesheet": "\n            * { model: claude-opus-4-7; }\n        ",
-          "current_node": "preflight_lint",
+          "current_node": "implement",
           "internal.retry_count.preflight_compile": 0,
-          "internal.thread_id": "preflight_compile",
+          "internal.thread_id": "preflight_lint",
+          "response.implement": "All verification steps pass. Summary:\n\nThe plan was already fully implemented in the working tree:\n\n1. **`lib/crates/fabro-model/src/billing.rs`** — `BilledTokenCounts::token_counts()` and `Catalog::price_tokens()` are present (lines 363-372 and 458-471).\n\n2. **`lib/crates/fabro-workflow/src/billing_rollup.rs`** — `billing_rollup_from_projection` takes `catalog: Option<&Catalog>`, `stage_usage_with_cost` helper is in place, and the new `rollup_prices_in_flight_stage_usage_using_catalog` test exists alongside updated existing tests.\n\n3. **Call sites** — All updated:\n   - `fabro-server/src/server/handler/billing.rs:82-83` — passes `Some(&catalog)` from `state.catalog()`.\n   - `fabro-server/src/server.rs:3337,3622` — aggregate-billing sites pass `None`.\n   - `fabro-workflow/src/pipeline/finalize.rs:85,442,558,983` — all four sites pass `None`.\n\nVerification (all green):\n- ✅ `cargo nextest run -p fabro-workflow billing_rollup` — 4 tests pass (incl. new in-flight pricing test)\n- ✅ `cargo nextest run -p fabro-server billing` — 7 tests pass\n- ✅ `cargo build --workspace`\n- ✅ `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`",
           "outcome": "succeeded"
         },
         "node_outcomes": {
@@ -725,6 +812,38 @@
             "notes": "Script completed: command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1",
             "usage": null
           },
+          "implement": {
+            "status": "succeeded",
+            "context_updates": {
+              "last_stage": "implement",
+              "last_response": "All verification steps pass. Summary:\n\nThe plan was already fully implemented in the working tree:\n\n1. **`lib/crates/fabro-model/src/billing.rs`** — `BilledTokenCounts::token_counts()` and `Catalog:",
+              "response.implement": "All verification steps pass. Summary:\n\nThe plan was already fully implemented in the working tree:\n\n1. **`lib/crates/fabro-model/src/billing.rs`** — `BilledTokenCounts::token_counts()` and `Catalog::price_tokens()` are present (lines 363-372 and 458-471).\n\n2. **`lib/crates/fabro-workflow/src/billing_rollup.rs`** — `billing_rollup_from_projection` takes `catalog: Option<&Catalog>`, `stage_usage_with_cost` helper is in place, and the new `rollup_prices_in_flight_stage_usage_using_catalog` test exists alongside updated existing tests.\n\n3. **Call sites** — All updated:\n   - `fabro-server/src/server/handler/billing.rs:82-83` — passes `Some(&catalog)` from `state.catalog()`.\n   - `fabro-server/src/server.rs:3337,3622` — aggregate-billing sites pass `None`.\n   - `fabro-workflow/src/pipeline/finalize.rs:85,442,558,983` — all four sites pass `None`.\n\nVerification (all green):\n- ✅ `cargo nextest run -p fabro-workflow billing_rollup` — 4 tests pass (incl. new in-flight pricing test)\n- ✅ `cargo nextest run -p fabro-server billing` — 7 tests pass\n- ✅ `cargo build --workspace`\n- ✅ `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`"
+            },
+            "notes": "Stage completed: implement",
+            "usage": {
+              "input": {
+                "usage": {
+                  "model": {
+                    "provider": "anthropic",
+                    "model_id": "claude-opus-4-7"
+                  },
+                  "tokens": {
+                    "input_tokens": 38163,
+                    "output_tokens": 2132,
+                    "reasoning_tokens": 0,
+                    "cache_read_tokens": 353207,
+                    "cache_write_tokens": 51130
+                  }
+                },
+                "facts": {
+                  "algorithm": "anthropic",
+                  "cache_write_5m_tokens": 51130,
+                  "cache_write_1h_tokens": 0
+                }
+              },
+              "total_usd_micros": 740280
+            }
+          },
           "preflight_lint": {
             "status": "succeeded",
             "context_updates": {
@@ -746,10 +865,11 @@
             "usage": null
           }
         },
-        "next_node_id": "implement",
+        "next_node_id": "simplify_opus",
         "node_visits": {
           "start": 1,
           "toolchain": 1,
+          "implement": 1,
           "preflight_compile": 1,
           "preflight_lint": 1
         }
@@ -782,7 +902,12 @@
       "first_event_seq": 40,
       "prompt": null,
       "response": null,
-      "completion": null,
+      "completion": {
+        "outcome": "succeeded",
+        "notes": "Script completed: cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1",
+        "failure_reason": null,
+        "timestamp": "2026-05-22T02:09:41.309136Z"
+      },
       "provider_used": null,
       "diff": null,
       "script_invocation": {
@@ -790,11 +915,27 @@
         "command": "exec 2>&1\ncargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1",
         "language": "shell"
       },
-      "script_timing": null,
+      "script_timing": {
+        "output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126",
+        "exit_code": 0,
+        "duration_ms": 136127,
+        "termination": "exited",
+        "output_bytes": 0,
+        "live_streaming": false
+      },
       "parallel_results": null,
       "output": null,
+      "output_bytes": 0,
+      "live_streaming": false,
+      "termination": "exited",
       "started_at": "2026-05-22T02:07:25.169483Z",
       "handler": "command",
+      "timing": {
+        "wall_time_ms": 136138,
+        "inference_time_ms": 0,
+        "tool_time_ms": 0,
+        "active_time_ms": 0
+      },
       "usage": {
         "input_tokens": 0,
         "output_tokens": 0,
@@ -803,7 +944,7 @@
         "cache_read_tokens": 0,
         "cache_write_tokens": 0
       },
-      "state": "running"
+      "state": "succeeded"
     },
     "preflight_compile@1": {
       "first_event_seq": 30,
@@ -853,6 +994,38 @@
       },
       "state": "succeeded"
     },
+    "implement@1": {
+      "first_event_seq": 50,
+      "prompt": null,
+      "response": null,
+      "completion": null,
+      "provider_used": {
+        "mode": "agent",
+        "provider": "anthropic",
+        "model": "claude-opus-4-7"
+      },
+      "diff": null,
+      "script_invocation": null,
+      "script_timing": null,
+      "parallel_results": null,
+      "output": null,
+      "started_at": "2026-05-22T02:09:45.572360Z",
+      "handler": "agent",
+      "usage": {
+        "input_tokens": 38163,
+        "output_tokens": 2132,
+        "total_tokens": 444632,
+        "reasoning_tokens": 0,
+        "cache_read_tokens": 353207,
+        "cache_write_tokens": 51130,
+        "total_usd_micros": 740280
+      },
+      "model": {
+        "provider": "anthropic",
+        "model_id": "claude-opus-4-7"
+      },
+      "state": "running"
+    },
     "start@1": {
       "first_event_seq": 16,
       "prompt": null,
diff --git a/stages/004-preflight_lint@1/output.log b/stages/004-preflight_lint@1/output.log
new file mode 100644
index 000000000..d87ba9545
--- /dev/null
+++ b/stages/004-preflight_lint@1/output.log
@@ -0,0 +1 @@
+blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126
\ No newline at end of file
diff --git a/stages/004-preflight_lint@1/script_timing.json b/stages/004-preflight_lint@1/script_timing.json
new file mode 100644
index 000000000..594ca87c3
--- /dev/null
+++ b/stages/004-preflight_lint@1/script_timing.json
@@ -0,0 +1,8 @@
+{
+  "output": "blob://sha256/12ae32cb1ec02d01eda3581b127c1fee3b0dc53572ed6baf239721a03d82e126",
+  "exit_code": 0,
+  "duration_ms": 136127,
+  "termination": "exited",
+  "output_bytes": 0,
+  "live_streaming": false
+}
\ No newline at end of file
diff --git a/stages/004-preflight_lint@1/status.json b/stages/004-preflight_lint@1/status.json
new file mode 100644
index 000000000..80dac72bd
--- /dev/null
+++ b/stages/004-preflight_lint@1/status.json
@@ -0,0 +1,6 @@
+{
+  "outcome": "succeeded",
+  "notes": "Script completed: cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1",
+  "failure_reason": null,
+  "timestamp": "2026-05-22T02:09:41.309136Z"
+}
\ No newline at end of file
diff --git a/stages/005-implement@1/prompt.md b/stages/005-implement@1/prompt.md
new file mode 100644
index 000000000..a3ee2ef86
--- /dev/null
+++ b/stages/005-implement@1/prompt.md
@@ -0,0 +1,104 @@
+Goal: # Plan: Compute LLM cost on-read for in-flight stages
+
+## Context
+
+On the run billing page (`/runs/{id}/billing`), an active stage shows token
+usage but no dollar cost — cost renders as `—` until the stage completes.
+
+Root cause: while a stage runs, `AgentMessage` events carry usage built by
+`billed_token_counts_from_llm` (`fabro-workflow/src/outcome.rs:43`), which
+hard-codes `total_usd_micros: None`. Dollar cost is only computed by
+`billed_model_usage_from_llm` (`outcome.rs:14`) — which needs the pricing
+`Catalog` — and that runs only on `StageCompleted`/`PromptCompleted`/`StageFailed`.
+So an in-flight stage's `StageProjection.usage.total_usd_micros` stays `None`.
+
+Fix: price stages whose cost is `None` when the billing rollup is built for a
+read request, using the model + token counts already in the projection. The
+wire contract is unchanged (`total_usd_micros` is already nullable everywhere)
+and the frontend already renders whatever value comes back — no UI change.
+
+## Decisions
+
+- **Price any stage with `total_usd_micros == None`**, not just in-flight ones.
+  Completed stages with unpriceable providers (`BillingPolicy::None`) return
+  `None` again — harmless; no need to thread `StageState`.
+- **No "estimated" label.** Cost-so-far is exact for tokens consumed so far,
+  matching the already-unlabeled live token counts and ticking runtime.
+- **Aggregate billing stays finalized-only.** The `BillingAccumulator` call
+  sites pass `None` so a run's running estimate is never folded into org-wide
+  totals (avoids double-count when the run later finalizes).
+- Per-stage rows, `totals`, and `by_model` are all priced from the same source
+  so the billing page stays internally consistent.
+
+## Changes
+
+### 1. `lib/crates/fabro-model/src/billing.rs`
+
+- Add `BilledTokenCounts::token_counts(&self) -> TokenCounts` — drops
+  `total_tokens`/`total_usd_micros`, keeps the five disjoint buckets.
+- Add `Catalog::price_tokens(&self, model: &ModelRef, tokens: &TokenCounts) -> Option<i64>`
+  next to `pricing_for`/`billing_facts_for`. Body mirrors the cost lines of
+  `billed_model_usage_from_llm`: build `ModelBillingFacts` via
+  `billing_facts_for`, assemble `ModelBillingInput { ModelUsage { model, tokens }, facts }`,
+  then `pricing_for(model).and_then(|p| p.bill(&input)).map(|a| a.0)`. Returns
+  `None` when the provider has no billing policy.
+
+### 2. `lib/crates/fabro-workflow/src/billing_rollup.rs`
+
+- Change signature to
+  `billing_rollup_from_projection(projection: &RunProjection, catalog: Option<&Catalog>)`.
+- Add a module-private helper `stage_usage_with_cost(catalog, stage) -> BilledTokenCounts`:
+  clone `stage.usage`; if `total_usd_micros.is_none()` and both `catalog` and
+  `stage.model` are present, set it via `catalog.price_tokens(model, &usage.token_counts())`.
+- In the loop, compute `priced` once per stage and use it in place of
+  `&stage.usage` for the `is_zero` check, `row.billing.add_counts`,
+  `totals.add_counts`, and `model_entry.billing.add_counts`.
+- Update the existing tests to pass `None`; add one new test: an in-flight
+  stage (no `completion`, non-zero `usage` with `total_usd_micros: None`, a
+  builtin `model`) yields `Some(..)` cost on the stage row and in `totals` when
+  called with `Some(Catalog::builtin())`.
+
+### 3. Call sites of `billing_rollup_from_projection`
+
+- `lib/crates/fabro-server/src/server/handler/billing.rs:82` — bind
+  `let catalog = state.catalog();` (returns `Arc<Catalog>`) and pass
+  `Some(&catalog)`.
+- `lib/crates/fabro-server/src/server.rs` (2 aggregate-billing sites) — pass `None`.
+- `lib/crates/fabro-workflow/src/pipeline/finalize.rs` (4 sites) — pass `None`
+  (stages already priced at completion; pricing would be a no-op anyway).
+
+No changes to `fabro-api.yaml`, the generated clients, or `apps/fabro-web`.
+
+## Out of scope / known limitation
+
+In-flight **prompt** stages have no `model` until `PromptCompleted` (only
+`AgentMessage` sets `stage.model` mid-run), so they still show `—` while
+running. Acceptable: prompt stages are a single short LLM call. The bug report
+concerns agent stages, where `model` is available.
+
+## Verification
+
+- `cargo nextest run -p fabro-workflow billing_rollup` — new + updated unit tests pass.
+- `cargo nextest run -p fabro-server billing` — handler conformance still passes.
+- `cargo build --workspace` and `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`.
+- Manual: `fabro server start` + `cd apps/fabro-web && bun run dev`, start a
+  workflow with an agent stage, open `/runs/{id}/billing` mid-run — the active
+  stage row and totals show a non-`—` dollar amount that grows with tokens.
+
+
+## Completed stages
+- **toolchain**: succeeded
+  - Script: `command -v cargo >/dev/null || { curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && sudo ln -sf $HOME/.cargo/bin/* /usr/local/bin/; }; cargo --version 2>&1`
+  - Output:
+    ```
+    cargo 1.95.0 (f2d3ce0bd 2026-03-21)
+    ```
+- **preflight_compile**: succeeded
+  - Script: `cargo check -q --workspace 2>&1`
+  - Output: (empty)
+- **preflight_lint**: succeeded
+  - Script: `cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1`
+  - Output: (empty)
+
+
+Read the plan file referenced in the goal and implement every step. Make all the code changes described in the plan. Use red/green TDD.
\ No newline at end of file
diff --git a/stages/005-implement@1/provider_used.json b/stages/005-implement@1/provider_used.json
new file mode 100644
index 000000000..672cc50e5
--- /dev/null
+++ b/stages/005-implement@1/provider_used.json
@@ -0,0 +1,5 @@
+{
+  "mode": "agent",
+  "provider": "anthropic",
+  "model": "claude-opus-4-7"
+}
\ No newline at end of file
diff --git a/stages/005-implement@1/response.md b/stages/005-implement@1/response.md
new file mode 100644
index 000000000..227f59ee8
--- /dev/null
+++ b/stages/005-implement@1/response.md
@@ -0,0 +1,18 @@
+All verification steps pass. Summary:
+
+The plan was already fully implemented in the working tree:
+
+1. **`lib/crates/fabro-model/src/billing.rs`** — `BilledTokenCounts::token_counts()` and `Catalog::price_tokens()` are present (lines 363-372 and 458-471).
+
+2. **`lib/crates/fabro-workflow/src/billing_rollup.rs`** — `billing_rollup_from_projection` takes `catalog: Option<&Catalog>`, `stage_usage_with_cost` helper is in place, and the new `rollup_prices_in_flight_stage_usage_using_catalog` test exists alongside updated existing tests.
+
+3. **Call sites** — All updated:
+   - `fabro-server/src/server/handler/billing.rs:82-83` — passes `Some(&catalog)` from `state.catalog()`.
+   - `fabro-server/src/server.rs:3337,3622` — aggregate-billing sites pass `None`.
+   - `fabro-workflow/src/pipeline/finalize.rs:85,442,558,983` — all four sites pass `None`.
+
+Verification (all green):
+- ✅ `cargo nextest run -p fabro-workflow billing_rollup` — 4 tests pass (incl. new in-flight pricing test)
+- ✅ `cargo nextest run -p fabro-server billing` — 7 tests pass
+- ✅ `cargo build --workspace`
+- ✅ `cargo +nightly-2026-04-14 clippy --workspace --all-targets -- -D warnings`
\ No newline at end of file