checkpoint

⚒️ Generated with [Fabro](https://fabro.sh)

checkpoint.json

@@ -1,6 +1,6 @@
 {
-  "timestamp": "2026-03-16T02:15:54.991394Z",
-  "current_node": "simplify_gemini",
+  "timestamp": "2026-03-16T02:19:16.696887Z",
+  "current_node": "simplify_gpt",
   "completed_nodes": [
     "start",
     "toolchain",
@@ -8,44 +8,49 @@
     "preflight_lint",
     "implement",
     "simplify_opus",
-    "simplify_gemini"
+    "simplify_gemini",
+    "simplify_gpt"
   ],
   "node_retries": {
+    "simplify_gemini": 1,
+    "simplify_gpt": 1,
     "preflight_compile": 1,
     "start": 1,
     "simplify_opus": 1,
-    "simplify_gemini": 1,
+    "toolchain": 1,
     "preflight_lint": 1,
-    "implement": 1,
-    "toolchain": 1
+    "implement": 1
   },
   "context_values": {
-    "last_response": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &Ag",
+    "last_response": "All 7 tests in the module pass, including the 4 new `track_file_event` tests. Clippy is clean.\n\n## Summary\n\nAll three review agents completed. Here's the aggregate:\n\n- **Code Reuse:** No issues — no",
     "internal.run_id": "01KKT5VYJ8FG6KX44AVXK8PY96",
     "command.stderr": "",
-    "last_stage": "simplify_gemini",
+    "last_stage": "simplify_gpt",
     "graph.model_stylesheet": "\n            * { backend: api; model: claude-opus-4-6;}\n        ",
-    "internal.thread_id": "simplify_opus",
+    "internal.thread_id": "simplify_gemini",
     "command.output": "",
     "graph.goal": "# Fix: Sub-agent file writes not tracked in API backend\n\n## Context\n\nWhen the API backend's agent spawns sub-agents that call `edit_file`/`write_file`, those files are missing from `outcome.files_touched`. This causes downstream nodes (like `simplify_opus`) to receive an incomplete file list in their prompt preamble.\n\nRoot cause: `spawn_event_forwarder` in `backend.rs` only matches top-level `ToolCallStarted`/`ToolCallCompleted` events. Sub-agent tool calls arrive wrapped as `AgentEvent::SubAgentEvent { event: Box<inner> }` and hit the `_ => {}` catch-all.\n\n## Plan\n\n**Single file change:** `lib/crates/fabro-workflows/src/cli/backend.rs`\n\nIn `spawn_event_forwarder` (line 51), replace the flat match with a helper that recursively unwraps `SubAgentEvent` to extract the inner `ToolCallStarted`/`ToolCallCompleted`:\n\n```\nmatch &event.event {\n    AgentEvent::ToolCallStarted { .. } => { /* existing logic */ }\n    AgentEvent::ToolCallCompleted { .. } => { /* existing logic */ }\n+   AgentEvent::SubAgentEvent { event: inner, .. } => {\n+       // Recursively extract file-tracking events from sub-agents\n+       track_file_event(inner, &pending_tool_calls, &files_touched, &last_file_touched);\n+   }\n    _ => {}\n}\n```\n\nExtract the file-tracking logic into a `track_file_event(event, pending, touched, last)` function that:\n1. Matches `ToolCallStarted` for `write_file`/`edit_file` → records to `pending_tool_calls`\n2. Matches `ToolCallCompleted` (non-error) → moves from pending to `files_touched`\n3. Matches `SubAgentEvent` → recurses into the inner event (handles sub-sub-agents)\n4. Otherwise → no-op\n\nThe existing inline match in `spawn_event_forwarder` calls `track_file_event` for both top-level and sub-agent events.\n\n## Verification\n\n1. `cargo test -p fabro-workflows` — existing tests pass\n2. `cargo clippy --workspace -- -D warnings` — clean\n3. Add a unit test: emit a `SubAgentEvent` wrapping a `ToolCallStarted`/`ToolCallCompleted` for `edit_file`, verify it appears in `files_touched`\n",
     "internal.retry_count.start": 1,
     "response.simplify_gemini": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>)` to `fn track_file_event(event: &AgentEvent, state: &mut FileTracking)`. The caller in `spawn_event_forwarder` now locks once and passes `&mut`. This:\n- Removes coupling of a pure state-transition function to the concurrency wrapper\n- Simplifies all 4 tests (no more `Arc<Mutex<>>` scaffolding — direct `&mut` access)\n- Makes the function more composable if reused elsewhere\n\n**Findings skipped (not worth addressing):**\n- *FileTracking vs FileTracker duplication*: The existing `FileTracker` in `fabro-agent` doesn't handle sub-agent events. Fixing that would require cross-crate changes beyond scope.\n- *Stringly-typed tool names*: No constants exist anywhere in the codebase. Adding a constants system is a broader effort.\n- *Missing `apply_patch` coverage*: Pre-existing gap (old code also only tracked `write_file`/`edit_file`). `apply_patch` extracts paths from output, not arguments, so it needs a different approach.\n- *`last` as derived state*: Part of the existing design pre-dating this diff.",
     "internal.retry_count.toolchain": 1,
     "thread.preflight_compile.current_node": "preflight_lint",
+    "thread.simplify_gemini.current_node": "simplify_gpt",
     "thread.toolchain.current_node": "preflight_compile",
     "failure_signature": "",
     "thread.implement.current_node": "simplify_opus",
     "internal.retry_count.implement": 1,
     "thread.preflight_lint.current_node": "implement",
     "outcome": "success",
-    "current.preamble": "Goal: # Fix: Sub-agent file writes not tracked in API backend\n\n## Context\n\nWhen the API backend's agent spawns sub-agents that call `edit_file`/`write_file`, those files are missing from `outcome.files_touched`. This causes downstream nodes (like `simplify_opus`) to receive an incomplete file list in their prompt preamble.\n\nRoot cause: `spawn_event_forwarder` in `backend.rs` only matches top-level `ToolCallStarted`/`ToolCallCompleted` events. Sub-agent tool calls arrive wrapped as `AgentEvent::SubAgentEvent { event: Box<inner> }` and hit the `_ => {}` catch-all.\n\n## Plan\n\n**Single file change:** `lib/crates/fabro-workflows/src/cli/backend.rs`\n\nIn `spawn_event_forwarder` (line 51), replace the flat match with a helper that recursively unwraps `SubAgentEvent` to extract the inner `ToolCallStarted`/`ToolCallCompleted`:\n\n```\nmatch &event.event {\n    AgentEvent::ToolCallStarted { .. } => { /* existing logic */ }\n    AgentEvent::ToolCallCompleted { .. } => { /* existing logic */ }\n+   AgentEvent::SubAgentEvent { event: inner, .. } => {\n+       // Recursively extract file-tracking events from sub-agents\n+       track_file_event(inner, &pending_tool_calls, &files_touched, &last_file_touched);\n+   }\n    _ => {}\n}\n```\n\nExtract the file-tracking logic into a `track_file_event(event, pending, touched, last)` function that:\n1. Matches `ToolCallStarted` for `write_file`/`edit_file` → records to `pending_tool_calls`\n2. Matches `ToolCallCompleted` (non-error) → moves from pending to `files_touched`\n3. Matches `SubAgentEvent` → recurses into the inner event (handles sub-sub-agents)\n4. Otherwise → no-op\n\nThe existing inline match in `spawn_event_forwarder` calls `track_file_event` for both top-level and sub-agent events.\n\n## Verification\n\n1. `cargo test -p fabro-workflows` — existing tests pass\n2. `cargo clippy --workspace -- -D warnings` — clean\n3. Add a unit test: emit a `SubAgentEvent` wrapping a `ToolCallStarted`/`ToolCallCompleted` for `edit_file`, verify it appears in `files_touched`\n\n\n## Completed stages\n- **toolchain**: success\n  - 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`\n  - Stdout:\n    ```\n    cargo 1.94.0 (85eff7c80 2026-01-15)\n    ```\n  - Stderr: (empty)\n- **preflight_compile**: success\n  - Script: `cargo check -q --workspace 2>&1`\n  - Stdout: (empty)\n  - Stderr: (empty)\n- **preflight_lint**: success\n  - Script: `cargo clippy -q --workspace -- -D warnings 2>&1`\n  - Stdout: (empty)\n  - Stderr: (empty)\n- **implement**: success\n  - Model: claude-opus-4-6, 23.4k tokens in / 7.5k out\n  - Files: /home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs\n- **simplify_opus**: success\n  - Model: claude-opus-4-6, 33.6k tokens in / 5.2k out\n",
+    "current.preamble": "Goal: # Fix: Sub-agent file writes not tracked in API backend\n\n## Context\n\nWhen the API backend's agent spawns sub-agents that call `edit_file`/`write_file`, those files are missing from `outcome.files_touched`. This causes downstream nodes (like `simplify_opus`) to receive an incomplete file list in their prompt preamble.\n\nRoot cause: `spawn_event_forwarder` in `backend.rs` only matches top-level `ToolCallStarted`/`ToolCallCompleted` events. Sub-agent tool calls arrive wrapped as `AgentEvent::SubAgentEvent { event: Box<inner> }` and hit the `_ => {}` catch-all.\n\n## Plan\n\n**Single file change:** `lib/crates/fabro-workflows/src/cli/backend.rs`\n\nIn `spawn_event_forwarder` (line 51), replace the flat match with a helper that recursively unwraps `SubAgentEvent` to extract the inner `ToolCallStarted`/`ToolCallCompleted`:\n\n```\nmatch &event.event {\n    AgentEvent::ToolCallStarted { .. } => { /* existing logic */ }\n    AgentEvent::ToolCallCompleted { .. } => { /* existing logic */ }\n+   AgentEvent::SubAgentEvent { event: inner, .. } => {\n+       // Recursively extract file-tracking events from sub-agents\n+       track_file_event(inner, &pending_tool_calls, &files_touched, &last_file_touched);\n+   }\n    _ => {}\n}\n```\n\nExtract the file-tracking logic into a `track_file_event(event, pending, touched, last)` function that:\n1. Matches `ToolCallStarted` for `write_file`/`edit_file` → records to `pending_tool_calls`\n2. Matches `ToolCallCompleted` (non-error) → moves from pending to `files_touched`\n3. Matches `SubAgentEvent` → recurses into the inner event (handles sub-sub-agents)\n4. Otherwise → no-op\n\nThe existing inline match in `spawn_event_forwarder` calls `track_file_event` for both top-level and sub-agent events.\n\n## Verification\n\n1. `cargo test -p fabro-workflows` — existing tests pass\n2. `cargo clippy --workspace -- -D warnings` — clean\n3. Add a unit test: emit a `SubAgentEvent` wrapping a `ToolCallStarted`/`ToolCallCompleted` for `edit_file`, verify it appears in `files_touched`\n\n\n## Completed stages\n- **toolchain**: success\n  - 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`\n  - Stdout:\n    ```\n    cargo 1.94.0 (85eff7c80 2026-01-15)\n    ```\n  - Stderr: (empty)\n- **preflight_compile**: success\n  - Script: `cargo check -q --workspace 2>&1`\n  - Stdout: (empty)\n  - Stderr: (empty)\n- **preflight_lint**: success\n  - Script: `cargo clippy -q --workspace -- -D warnings 2>&1`\n  - Stdout: (empty)\n  - Stderr: (empty)\n- **implement**: success\n  - Model: claude-opus-4-6, 23.4k tokens in / 7.5k out\n  - Files: /home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs\n- **simplify_opus**: success\n  - Model: claude-opus-4-6, 33.6k tokens in / 5.2k out\n- **simplify_gemini**: success\n  - Model: claude-opus-4-6, 38.6k tokens in / 11.5k out\n  - Files: /home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs\n",
     "response.implement": "Everything looks correct. Here's a summary of what was done:\n\n## Changes Made\n\n**File:** `lib/crates/fabro-workflows/src/cli/backend.rs`\n\n### 1. Extracted `track_file_event` helper function (lines 33–75)\n\nA new recursive function that handles file-tracking logic for `write_file`/`edit_file` tool calls:\n- **`ToolCallStarted`** → records the `file_path` argument in `pending_tool_calls` keyed by `tool_call_id`\n- **`ToolCallCompleted`** (non-error) → moves the path from `pending_tool_calls` to `files_touched` and updates `last_file_touched`\n- **`ToolCallCompleted`** (error) → removes from `pending_tool_calls` without recording\n- **`SubAgentEvent`** → recursively unwraps the inner event and calls itself (handles arbitrarily nested sub-agents)\n- Everything else → no-op\n\n### 2. Refactored `spawn_event_forwarder` to use `track_file_event`\n\nReplaced the inline `match` block with a single call to `track_file_event(&event.event, ...)`, which now handles both top-level and sub-agent events.\n\n### 3. Added 4 unit tests\n\n- `track_file_event_records_top_level_write` — verifies basic `write_file` tracking still works\n- `track_file_event_unwraps_sub_agent_edit` — verifies `SubAgentEvent`-wrapped `edit_file` calls are tracked\n- `track_file_event_unwraps_nested_sub_sub_agent` — verifies double-nested `SubAgentEvent` (sub-sub-agent) is handled\n- `track_file_event_error_removes_pending` — verifies errored sub-agent tool calls don't pollute `files_touched`\n\n### Verification\n- ✅ `cargo test -p fabro-workflows` — 179 passed, 0 failed\n- ✅ `cargo clippy --workspace -- -D warnings` — clean",
     "internal.fidelity": "compact",
+    "response.simplify_gpt": "All 7 tests in the module pass, including the 4 new `track_file_event` tests. Clippy is clean.\n\n## Summary\n\nAll three review agents completed. Here's the aggregate:\n\n- **Code Reuse:** No issues — no duplication of existing utilities found.\n- **Code Quality:** No issues — the `FileTracking` struct and `track_file_event` function are well-structured, properly documented, and the tests cover top-level events, single-wrapped sub-agent events, double-wrapped sub-sub-agent events, and error paths.\n- **Efficiency:** One minor finding — the mutex is acquired on every event (including streaming deltas that don't need tracking). Skipped as not worth fixing: the mutex is uncontended (~20ns), event rates are manageable (hundreds/sec), and consolidating from 3 `Arc<Mutex<...>>` to 1 is already a net improvement. Adding a pre-check would add complexity (double-traversal of `SubAgentEvent` wrappers) for negligible benefit.\n\n**The code is already clean. No changes needed.**",
     "thread.start.current_node": "toolchain",
     "internal.retry_count.simplify_opus": 1,
     "internal.retry_count.preflight_compile": 1,
+    "internal.retry_count.simplify_gpt": 1,
     "graph.rankdir": "LR",
-    "current_node": "simplify_gemini",
+    "current_node": "simplify_gpt",
     "thread.simplify_opus.current_node": "simplify_gemini",
     "failure_class": "",
     "response.simplify_opus": "Everything is clean. Here's a summary:\n\n## Summary\n\n**All three review agents found the code to be clean overall.** One improvement was identified and applied:\n\n### Fixed: Consolidated `FileTracking` struct\nThe three separate `Arc<Mutex<...>>` parameters (`pending_tool_calls`, `files_touched`, `last_file_touched`) were consolidated into a single `FileTracking` struct behind one `Arc<Mutex<...>>`. This was independently recommended by both the **Code Quality** agent (parameter sprawl) and the **Efficiency** agent (triple lock acquisition). The change:\n\n- **Reduces lock acquisitions** from 3 to 1 on the `ToolCallCompleted` success path\n- **Reduces parameter count** on `track_file_event` (4 → 2) and `spawn_event_forwarder` (6 → 4)\n- **Makes state updates atomic** — `touched` and `last` are updated under a single lock guard\n- **Reduces `Arc::clone` calls** at call sites from 3 to 1\n\n### No issues found (confirmed clean):\n- **Code Reuse**: No existing utilities for recursive `SubAgentEvent` unwrapping or event-based file tracking. The implementation is genuinely new.\n- **Stringly-typed tool names**: `\"write_file\"` / `\"edit_file\"` are consistent with the codebase convention — no constants exist anywhere.\n- **Recursion depth**: Bounded by `max_subagent_depth` (default 1), so stack depth is not a concern.\n- **Hot-path performance**: Non-file events hit the `_ => {}` arm immediately — negligible cost.\n- **Missing newline at EOF**: Fixed.",
@@ -55,6 +60,56 @@
   },
   "logs": [],
   "node_outcomes": {
+    "simplify_gpt": {
+      "status": "success",
+      "context_updates": {
+        "last_stage": "simplify_gpt",
+        "last_response": "All 7 tests in the module pass, including the 4 new `track_file_event` tests. Clippy is clean.\n\n## Summary\n\nAll three review agents completed. Here's the aggregate:\n\n- **Code Reuse:** No issues — no",
+        "response.simplify_gpt": "All 7 tests in the module pass, including the 4 new `track_file_event` tests. Clippy is clean.\n\n## Summary\n\nAll three review agents completed. Here's the aggregate:\n\n- **Code Reuse:** No issues — no duplication of existing utilities found.\n- **Code Quality:** No issues — the `FileTracking` struct and `track_file_event` function are well-structured, properly documented, and the tests cover top-level events, single-wrapped sub-agent events, double-wrapped sub-sub-agent events, and error paths.\n- **Efficiency:** One minor finding — the mutex is acquired on every event (including streaming deltas that don't need tracking). Skipped as not worth fixing: the mutex is uncontended (~20ns), event rates are manageable (hundreds/sec), and consolidating from 3 `Arc<Mutex<...>>` to 1 is already a net improvement. Adding a pre-check would add complexity (double-traversal of `SubAgentEvent` wrappers) for negligible benefit.\n\n**The code is already clean. No changes needed.**"
+      },
+      "notes": "Stage completed: simplify_gpt",
+      "usage": {
+        "model": "claude-opus-4-6",
+        "input_tokens": 25500,
+        "output_tokens": 7424,
+        "cache_read_tokens": 143683,
+        "cache_write_tokens": 29881,
+        "reasoning_tokens": 582,
+        "cost": 0.9393
+      },
+      "duration_ms": 199534
+    },
+    "simplify_gemini": {
+      "status": "success",
+      "context_updates": {
+        "last_stage": "simplify_gemini",
+        "last_response": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &Ag",
+        "response.simplify_gemini": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>)` to `fn track_file_event(event: &AgentEvent, state: &mut FileTracking)`. The caller in `spawn_event_forwarder` now locks once and passes `&mut`. This:\n- Removes coupling of a pure state-transition function to the concurrency wrapper\n- Simplifies all 4 tests (no more `Arc<Mutex<>>` scaffolding — direct `&mut` access)\n- Makes the function more composable if reused elsewhere\n\n**Findings skipped (not worth addressing):**\n- *FileTracking vs FileTracker duplication*: The existing `FileTracker` in `fabro-agent` doesn't handle sub-agent events. Fixing that would require cross-crate changes beyond scope.\n- *Stringly-typed tool names*: No constants exist anywhere in the codebase. Adding a constants system is a broader effort.\n- *Missing `apply_patch` coverage*: Pre-existing gap (old code also only tracked `write_file`/`edit_file`). `apply_patch` extracts paths from output, not arguments, so it needs a different approach.\n- *`last` as derived state*: Part of the existing design pre-dating this diff."
+      },
+      "notes": "Stage completed: simplify_gemini",
+      "usage": {
+        "model": "claude-opus-4-6",
+        "input_tokens": 38584,
+        "output_tokens": 11462,
+        "cache_read_tokens": 338251,
+        "cache_write_tokens": 42558,
+        "reasoning_tokens": 1050,
+        "cost": 1.4384100000000002
+      },
+      "files_touched": [
+        "/home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs"
+      ],
+      "duration_ms": 335379
+    },
+    "preflight_compile": {
+      "status": "success",
+      "context_updates": {
+        "command.stderr": "",
+        "command.output": ""
+      },
+      "notes": "Script completed: cargo check -q --workspace 2>&1",
+      "duration_ms": 69914
+    },
     "implement": {
       "status": "success",
       "context_updates": {
@@ -86,28 +141,6 @@
       "notes": "Script completed: cargo clippy -q --workspace -- -D warnings 2>&1",
       "duration_ms": 16562
     },
-    "simplify_gemini": {
-      "status": "success",
-      "context_updates": {
-        "last_stage": "simplify_gemini",
-        "last_response": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &Ag",
-        "response.simplify_gemini": "Everything is clean. Here's the summary:\n\n## Summary\n\n**One issue fixed:**\n\n**Decoupled `track_file_event` from `Arc<Mutex<>>`** — Changed the function signature from `fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>)` to `fn track_file_event(event: &AgentEvent, state: &mut FileTracking)`. The caller in `spawn_event_forwarder` now locks once and passes `&mut`. This:\n- Removes coupling of a pure state-transition function to the concurrency wrapper\n- Simplifies all 4 tests (no more `Arc<Mutex<>>` scaffolding — direct `&mut` access)\n- Makes the function more composable if reused elsewhere\n\n**Findings skipped (not worth addressing):**\n- *FileTracking vs FileTracker duplication*: The existing `FileTracker` in `fabro-agent` doesn't handle sub-agent events. Fixing that would require cross-crate changes beyond scope.\n- *Stringly-typed tool names*: No constants exist anywhere in the codebase. Adding a constants system is a broader effort.\n- *Missing `apply_patch` coverage*: Pre-existing gap (old code also only tracked `write_file`/`edit_file`). `apply_patch` extracts paths from output, not arguments, so it needs a different approach.\n- *`last` as derived state*: Part of the existing design pre-dating this diff."
-      },
-      "notes": "Stage completed: simplify_gemini",
-      "usage": {
-        "model": "claude-opus-4-6",
-        "input_tokens": 38584,
-        "output_tokens": 11462,
-        "cache_read_tokens": 338251,
-        "cache_write_tokens": 42558,
-        "reasoning_tokens": 1050,
-        "cost": 1.4384100000000002
-      },
-      "files_touched": [
-        "/home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs"
-      ],
-      "duration_ms": 335379
-    },
     "start": {
       "status": "success",
       "duration_ms": 0
@@ -121,15 +154,6 @@
       "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",
       "duration_ms": 34
     },
-    "preflight_compile": {
-      "status": "success",
-      "context_updates": {
-        "command.stderr": "",
-        "command.output": ""
-      },
-      "notes": "Script completed: cargo check -q --workspace 2>&1",
-      "duration_ms": 69914
-    },
     "simplify_opus": {
       "status": "success",
       "context_updates": {
@@ -150,14 +174,15 @@
       "duration_ms": 345958
     }
   },
-  "next_node_id": "simplify_gpt",
+  "next_node_id": "verify",
   "node_visits": {
-    "implement": 1,
-    "preflight_compile": 1,
     "preflight_lint": 1,
     "simplify_gemini": 1,
     "toolchain": 1,
     "start": 1,
+    "simplify_gpt": 1,
+    "implement": 1,
+    "preflight_compile": 1,
     "simplify_opus": 1
   }
 }

nodes/simplify_gemini/diff.patch

@@ -0,0 +1,202 @@
+diff --git a/lib/crates/fabro-workflows/src/cli/backend.rs b/lib/crates/fabro-workflows/src/cli/backend.rs
+index 466d680..d33bf5a 100644
+--- a/lib/crates/fabro-workflows/src/cli/backend.rs
++++ b/lib/crates/fabro-workflows/src/cli/backend.rs
+@@ -42,7 +42,7 @@ struct FileTracking {
+ 
+ /// Recursively extract file-tracking events from agent events, including
+ /// those wrapped in one or more layers of `SubAgentEvent`.
+-fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>) {
++fn track_file_event(event: &AgentEvent, state: &mut FileTracking) {
+     match event {
+         AgentEvent::ToolCallStarted {
+             tool_name,
+@@ -51,11 +51,7 @@ fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>) {
+         } => {
+             if tool_name == "write_file" || tool_name == "edit_file" {
+                 if let Some(path) = arguments.get("file_path").and_then(|v| v.as_str()) {
+-                    state
+-                        .lock()
+-                        .unwrap()
+-                        .pending
+-                        .insert(tool_call_id.clone(), path.to_string());
++                    state.pending.insert(tool_call_id.clone(), path.to_string());
+                 }
+             }
+         }
+@@ -64,14 +60,13 @@ fn track_file_event(event: &AgentEvent, state: &Arc<Mutex<FileTracking>>) {
+             is_error,
+             ..
+         } => {
+-            let mut s = state.lock().unwrap();
+             if !*is_error {
+-                if let Some(path) = s.pending.remove(tool_call_id) {
+-                    s.touched.insert(path.clone());
+-                    s.last = Some(path);
++                if let Some(path) = state.pending.remove(tool_call_id) {
++                    state.touched.insert(path.clone());
++                    state.last = Some(path);
+                 }
+             } else {
+-                s.pending.remove(tool_call_id);
++                state.pending.remove(tool_call_id);
+             }
+         }
+         AgentEvent::SubAgentEvent { event: inner, .. } => {
+@@ -97,7 +92,7 @@ fn spawn_event_forwarder(
+             emitter.touch();
+ 
+             // Track file changes from tool calls (including sub-agent events)
+-            track_file_event(&event.event, &file_tracking);
++            track_file_event(&event.event, &mut file_tracking.lock().unwrap());
+ 
+             // Forward non-streaming agent events to pipeline
+             if !matches!(
+@@ -660,17 +655,17 @@ mod tests {
+         assert!(backend.sessions.lock().unwrap().is_empty());
+     }
+ 
+-    fn new_file_tracking() -> Arc<Mutex<FileTracking>> {
+-        Arc::new(Mutex::new(FileTracking {
++    fn new_file_tracking() -> FileTracking {
++        FileTracking {
+             pending: HashMap::new(),
+             touched: HashSet::new(),
+             last: None,
+-        }))
++        }
+     }
+ 
+     #[test]
+     fn track_file_event_records_top_level_write() {
+-        let state = new_file_tracking();
++        let mut state = new_file_tracking();
+ 
+         let mut args = serde_json::Map::new();
+         args.insert(
+@@ -684,12 +679,9 @@ mod tests {
+                 tool_call_id: "tc1".to_string(),
+                 arguments: serde_json::Value::Object(args),
+             },
+-            &state,
+-        );
+-        assert_eq!(
+-            state.lock().unwrap().pending.get("tc1").unwrap(),
+-            "/tmp/foo.rs"
++            &mut state,
+         );
++        assert_eq!(state.pending.get("tc1").unwrap(), "/tmp/foo.rs");
+ 
+         track_file_event(
+             &AgentEvent::ToolCallCompleted {
+@@ -698,16 +690,15 @@ mod tests {
+                 is_error: false,
+                 output: serde_json::Value::String("ok".to_string()),
+             },
+-            &state,
++            &mut state,
+         );
+-        let s = state.lock().unwrap();
+-        assert!(s.touched.contains("/tmp/foo.rs"));
+-        assert_eq!(s.last.as_deref(), Some("/tmp/foo.rs"));
++        assert!(state.touched.contains("/tmp/foo.rs"));
++        assert_eq!(state.last.as_deref(), Some("/tmp/foo.rs"));
+     }
+ 
+     #[test]
+     fn track_file_event_unwraps_sub_agent_edit() {
+-        let state = new_file_tracking();
++        let mut state = new_file_tracking();
+ 
+         let mut args = serde_json::Map::new();
+         args.insert(
+@@ -726,12 +717,9 @@ mod tests {
+                     arguments: serde_json::Value::Object(args),
+                 }),
+             },
+-            &state,
+-        );
+-        assert_eq!(
+-            state.lock().unwrap().pending.get("tc-sub").unwrap(),
+-            "/src/lib.rs"
++            &mut state,
+         );
++        assert_eq!(state.pending.get("tc-sub").unwrap(), "/src/lib.rs");
+ 
+         // ToolCallCompleted wrapped in SubAgentEvent
+         track_file_event(
+@@ -745,16 +733,15 @@ mod tests {
+                     output: serde_json::Value::String("ok".to_string()),
+                 }),
+             },
+-            &state,
++            &mut state,
+         );
+-        let s = state.lock().unwrap();
+-        assert!(s.touched.contains("/src/lib.rs"));
+-        assert_eq!(s.last.as_deref(), Some("/src/lib.rs"));
++        assert!(state.touched.contains("/src/lib.rs"));
++        assert_eq!(state.last.as_deref(), Some("/src/lib.rs"));
+     }
+ 
+     #[test]
+     fn track_file_event_unwraps_nested_sub_sub_agent() {
+-        let state = new_file_tracking();
++        let mut state = new_file_tracking();
+ 
+         let mut args = serde_json::Map::new();
+         args.insert(
+@@ -777,9 +764,9 @@ mod tests {
+                     }),
+                 }),
+             },
+-            &state,
++            &mut state,
+         );
+-        assert!(state.lock().unwrap().pending.contains_key("tc-deep"));
++        assert!(state.pending.contains_key("tc-deep"));
+ 
+         track_file_event(
+             &AgentEvent::SubAgentEvent {
+@@ -796,14 +783,14 @@ mod tests {
+                     }),
+                 }),
+             },
+-            &state,
++            &mut state,
+         );
+-        assert!(state.lock().unwrap().touched.contains("/deep/file.rs"));
++        assert!(state.touched.contains("/deep/file.rs"));
+     }
+ 
+     #[test]
+     fn track_file_event_error_removes_pending() {
+-        let state = new_file_tracking();
++        let mut state = new_file_tracking();
+ 
+         let mut args = serde_json::Map::new();
+         args.insert(
+@@ -821,7 +808,7 @@ mod tests {
+                     arguments: serde_json::Value::Object(args),
+                 }),
+             },
+-            &state,
++            &mut state,
+         );
+ 
+         track_file_event(
+@@ -835,11 +822,10 @@ mod tests {
+                     output: serde_json::Value::String("failed".to_string()),
+                 }),
+             },
+-            &state,
++            &mut state,
+         );
+-        let s = state.lock().unwrap();
+-        assert!(s.pending.is_empty());
+-        assert!(!s.touched.contains("/err.rs"));
++        assert!(state.pending.is_empty());
++        assert!(!state.touched.contains("/err.rs"));
+     }
+ 
+     #[test]

nodes/simplify_gpt/prompt.md

@@ -0,0 +1,117 @@
+Goal: # Fix: Sub-agent file writes not tracked in API backend
+
+## Context
+
+When the API backend's agent spawns sub-agents that call `edit_file`/`write_file`, those files are missing from `outcome.files_touched`. This causes downstream nodes (like `simplify_opus`) to receive an incomplete file list in their prompt preamble.
+
+Root cause: `spawn_event_forwarder` in `backend.rs` only matches top-level `ToolCallStarted`/`ToolCallCompleted` events. Sub-agent tool calls arrive wrapped as `AgentEvent::SubAgentEvent { event: Box<inner> }` and hit the `_ => {}` catch-all.
+
+## Plan
+
+**Single file change:** `lib/crates/fabro-workflows/src/cli/backend.rs`
+
+In `spawn_event_forwarder` (line 51), replace the flat match with a helper that recursively unwraps `SubAgentEvent` to extract the inner `ToolCallStarted`/`ToolCallCompleted`:
+
+```
+match &event.event {
+    AgentEvent::ToolCallStarted { .. } => { /* existing logic */ }
+    AgentEvent::ToolCallCompleted { .. } => { /* existing logic */ }
++   AgentEvent::SubAgentEvent { event: inner, .. } => {
++       // Recursively extract file-tracking events from sub-agents
++       track_file_event(inner, &pending_tool_calls, &files_touched, &last_file_touched);
++   }
+    _ => {}
+}
+```
+
+Extract the file-tracking logic into a `track_file_event(event, pending, touched, last)` function that:
+1. Matches `ToolCallStarted` for `write_file`/`edit_file` → records to `pending_tool_calls`
+2. Matches `ToolCallCompleted` (non-error) → moves from pending to `files_touched`
+3. Matches `SubAgentEvent` → recurses into the inner event (handles sub-sub-agents)
+4. Otherwise → no-op
+
+The existing inline match in `spawn_event_forwarder` calls `track_file_event` for both top-level and sub-agent events.
+
+## Verification
+
+1. `cargo test -p fabro-workflows` — existing tests pass
+2. `cargo clippy --workspace -- -D warnings` — clean
+3. Add a unit test: emit a `SubAgentEvent` wrapping a `ToolCallStarted`/`ToolCallCompleted` for `edit_file`, verify it appears in `files_touched`
+
+
+## Completed stages
+- **toolchain**: success
+  - 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`
+  - Stdout:
+    ```
+    cargo 1.94.0 (85eff7c80 2026-01-15)
+    ```
+  - Stderr: (empty)
+- **preflight_compile**: success
+  - Script: `cargo check -q --workspace 2>&1`
+  - Stdout: (empty)
+  - Stderr: (empty)
+- **preflight_lint**: success
+  - Script: `cargo clippy -q --workspace -- -D warnings 2>&1`
+  - Stdout: (empty)
+  - Stderr: (empty)
+- **implement**: success
+  - Model: claude-opus-4-6, 23.4k tokens in / 7.5k out
+  - Files: /home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs
+- **simplify_opus**: success
+  - Model: claude-opus-4-6, 33.6k tokens in / 5.2k out
+- **simplify_gemini**: success
+  - Model: claude-opus-4-6, 38.6k tokens in / 11.5k out
+  - Files: /home/daytona/workspace/lib/crates/fabro-workflows/src/cli/backend.rs
+
+
+# Simplify: Code Review and Cleanup
+
+Review all changed files for reuse, quality, and efficiency. Fix any issues found.
+
+## Phase 1: Identify Changes
+
+Run git diff (or git diff HEAD if there are staged changes) to see what changed. If there are no git changes, review the most recently modified files that the user mentioned or that you edited earlier in this conversation.
+
+## Phase 2: Launch Three Review Agents in Parallel
+
+Use the Agent tool to launch all three agents concurrently in a single message. Pass each agent the full diff so it has the complete context.
+
+### Agent 1: Code Reuse Review
+
+For each change:
+
+1. Search for existing utilities and helpers that could replace newly written code. Use Grep to find similar patterns elsewhere in the codebase — common locations are utility directories, shared modules, and files adjacent to the changed ones.
+2. Flag any new function that duplicates existing functionality. Suggest the existing function to use instead.
+3. Flag any inline logic that could use an existing utility — hand-rolled string manipulation, manual path handling, custom environment checks, ad-hoc type guards, and similar patterns are common candidates.
+
+Note: This is a greenfield app, so focus on maximizing simplicity and don't worry about changing things to achieve it.
+
+### Agent 2: Code Quality Review
+
+Review the same changes for hacky patterns:
+
+1. Redundant state: state that duplicates existing state, cached values that could be derived, observers/effects that could be direct calls
+2. Parameter sprawl: adding new parameters to a function instead of generalizing or restructuring existing ones
+3. Copy-paste with slight variation: near-duplicate code blocks that should be unified with a shared abstraction
+4. Leaky abstractions: exposing internal details that should be encapsulated, or breaking existing abstraction boundaries
+5. Stringly-typed code: using raw strings where constants, enums (string unions), or branded types already exist in the codebase
+
+Note: This is a greenfield app, so be aggressive in optimizing quality.
+
+### Agent 3: Efficiency Review
+
+Review the same changes for efficiency:
+
+1. Unnecessary work: redundant computations, repeated file reads, duplicate network/API calls, N+1 patterns
+2. Missed concurrency: independent operations run sequentially when they could run in parallel
+3. Hot-path bloat: new blocking work added to startup or per-request/per-render hot paths
+4. Unnecessary existence checks: pre-checking file/resource existence before operating (TOCTOU anti-pattern) — operate directly and handle the error
+5. Memory: unbounded data structures, missing cleanup, event listener leaks
+6. Overly broad operations: reading entire files when only a portion is needed, loading all items when filtering for one
+
+## Phase 3: Fix Issues
+
+Wait for all three agents to complete. Aggregate their findings and fix each issue directly. If a finding is a false positive or not worth addressing, note it and move on — do not argue with the finding, just skip it.
+
+When done, briefly summarize what was fixed (or confirm the code was already clean).

nodes/simplify_gpt/provider_used.json

@@ -0,0 +1,5 @@
+{
+  "mode": "agent",
+  "provider": "anthropic",
+  "model": "claude-opus-4-6"
+}

nodes/simplify_gpt/response.md

@@ -0,0 +1,11 @@
+All 7 tests in the module pass, including the 4 new `track_file_event` tests. Clippy is clean.
+
+## Summary
+
+All three review agents completed. Here's the aggregate:
+
+- **Code Reuse:** No issues — no duplication of existing utilities found.
+- **Code Quality:** No issues — the `FileTracking` struct and `track_file_event` function are well-structured, properly documented, and the tests cover top-level events, single-wrapped sub-agent events, double-wrapped sub-sub-agent events, and error paths.
+- **Efficiency:** One minor finding — the mutex is acquired on every event (including streaming deltas that don't need tracking). Skipped as not worth fixing: the mutex is uncontended (~20ns), event rates are manageable (hundreds/sec), and consolidating from 3 `Arc<Mutex<...>>` to 1 is already a net improvement. Adding a pre-check would add complexity (double-traversal of `SubAgentEvent` wrappers) for negligible benefit.
+
+**The code is already clean. No changes needed.**

nodes/simplify_gpt/status.json

@@ -0,0 +1,6 @@
+{
+  "status": "success",
+  "notes": "Stage completed: simplify_gpt",
+  "failure_reason": null,
+  "timestamp": "2026-03-16T02:19:16.695609+00:00"
+}