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stages/007-simplify_gpt@1/diff.patch

@@ -0,0 +1,356 @@
+diff --git a/lib/crates/fabro-workflow/src/pipeline/pull_request.rs b/lib/crates/fabro-workflow/src/pipeline/pull_request.rs
+index cd84af8b..8825f8ee 100644
+--- a/lib/crates/fabro-workflow/src/pipeline/pull_request.rs
++++ b/lib/crates/fabro-workflow/src/pipeline/pull_request.rs
+@@ -48,18 +48,6 @@ struct GeneratedPrContent {
+     body:  String,
+ }
+ 
+-/// LLM-derived PR title and the fully assembled body (LLM narrative plus
+-/// programmatic Plan / Retro / Fabro Details / footer sections).
+-///
+-/// `title` may be the empty string when the LLM returned a usable body but
+-/// no usable title — callers fall back to [`pr_title_from_goal`] in that
+-/// case. Every other generation failure is surfaced as `Err`.
+-#[derive(Debug, Clone)]
+-pub struct PrContent {
+-    pub title: String,
+-    pub body:  String,
+-}
+-
+ /// System prompt that instructs the LLM how to write a Fabro PR title and
+ /// body. The trailing programmatic sections (Plan `<details>`, Retro,
+ /// Fabro Details, footer) are appended after the LLM body — the prompt
+@@ -158,16 +146,12 @@ fn truncation_caps(model: &str) -> &'static TruncationCaps {
+     }
+ }
+ 
+-/// Truncate `s` to at most `max` bytes, aligned to a UTF-8 char boundary
+-/// (so the returned slice never splits a multibyte sequence). The cap is
+-/// in bytes for cheap context-window safety; for ASCII-heavy diffs and
+-/// goals this matches a char count.
++/// Truncate `s` to at most `max` Unicode scalar values without splitting a
++/// UTF-8 sequence.
+ fn truncate_chars(s: &str, max: usize) -> &str {
+-    if s.len() > max {
+-        &s[..s.floor_char_boundary(max)]
+-    } else {
+-        s
+-    }
++    s.char_indices()
++        .nth(max)
++        .map_or(s, |(boundary, _)| &s[..boundary])
+ }
+ 
+ /// Truncate `s` to at most `max` Unicode scalar values, replacing the
+@@ -454,7 +438,10 @@ async fn load_pull_request_diff(run_store: &RunStoreHandle) -> String {
+ /// Build a complete PR title and body by combining LLM-generated narrative
+ /// with programmatic sections (plan, retro, fabro details).
+ ///
+-/// See [`PrContent`] for the empty-title-as-fallback-signal contract.
++/// Returns `(title, body)`. The title may be the empty string when the LLM
++/// returned a usable body but no usable title — callers fall back to
++/// [`pr_title_from_goal`] in that case. Every other generation failure is
++/// surfaced as `Err`.
+ pub async fn build_pr_body(
+     diff: &str,
+     goal: &str,
+@@ -462,7 +449,7 @@ pub async fn build_pr_body(
+     run_store: &RunStoreHandle,
+     llm_source: &dyn CredentialSource,
+     conclusion: Option<&Conclusion>,
+-) -> Result<PrContent, String> {
++) -> Result<(String, String), String> {
+     let client = Client::from_source(llm_source)
+         .await
+         .map_err(|e| format!("Failed to create LLM client: {e}"))?;
+@@ -477,7 +464,7 @@ async fn build_pr_body_with_client(
+     run_store: &RunStoreHandle,
+     conclusion: Option<&Conclusion>,
+     client: Arc<Client>,
+-) -> Result<PrContent, String> {
++) -> Result<(String, String), String> {
+     build_pr_body_with_client_and_state(diff, goal, model, run_store, conclusion, client, None)
+         .await
+ }
+@@ -490,7 +477,7 @@ async fn build_pr_body_with_source_and_state(
+     llm_source: &dyn CredentialSource,
+     conclusion: Option<&Conclusion>,
+     run_state: Option<&fabro_store::RunProjection>,
+-) -> Result<PrContent, String> {
++) -> Result<(String, String), String> {
+     let client = Client::from_source(llm_source)
+         .await
+         .map_err(|e| format!("Failed to create LLM client: {e}"))?;
+@@ -515,7 +502,7 @@ async fn build_pr_body_with_client_and_state(
+     conclusion: Option<&Conclusion>,
+     client: Arc<Client>,
+     run_state: Option<&fabro_store::RunProjection>,
+-) -> Result<PrContent, String> {
++) -> Result<(String, String), String> {
+     info!("Building PR body");
+ 
+     let loaded_run_state = if run_state.is_none() {
+@@ -585,7 +572,7 @@ async fn build_pr_body_with_client_and_state(
+ 
+     info!("PR body generated");
+ 
+-    Ok(PrContent { title, body })
++    Ok((title, body))
+ }
+ 
+ /// Auto-merge configuration for a pull request.
+@@ -626,10 +613,7 @@ pub async fn maybe_open_pull_request(
+     let (owner, repo) =
+         github_app::parse_github_owner_repo(&https_url).map_err(|err| format!("{err:#}"))?;
+ 
+-    let PrContent {
+-        title: llm_title,
+-        body,
+-    } = build_pr_body_with_source_and_state(
++    let (llm_title, body) = build_pr_body_with_source_and_state(
+         req.diff,
+         req.goal,
+         req.model,
+@@ -642,14 +626,12 @@ pub async fn maybe_open_pull_request(
+     .map_err(|err| format!("{err:#}"))?;
+     let body = truncate_pr_body(&body);
+ 
+-    // The LLM-title path is already capped inside the builder via
+-    // `enforce_title_cap`; the fallback path uses `pr_title_from_goal`,
+-    // which has a wider 120-char cap and so needs re-capping here.
+     let title = if llm_title.is_empty() {
+-        enforce_title_cap(&pr_title_from_goal(req.goal))
++        pr_title_from_goal(req.goal)
+     } else {
+         llm_title
+     };
++    let title = enforce_title_cap(&title);
+ 
+     let created = github_app::create_pull_request(
+         &req.github,
+@@ -1307,7 +1289,7 @@ mod tests {
+     async fn build_pr_body_uses_in_memory_conclusion() {
+         let store = test_store();
+         let run_store = store.create_run(&fixtures::RUN_1).await.unwrap();
+-        let pr = build_pr_body_with_client(
++        let (title, body) = build_pr_body_with_client(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+             "Implement feature",
+             "mock-model",
+@@ -1321,8 +1303,7 @@ mod tests {
+         .await
+         .unwrap();
+ 
+-        assert_eq!(pr.title, "Mock title");
+-        let body = pr.body;
++        assert_eq!(title, "Mock title");
+         assert!(body.contains("Narrative from mock."));
+         assert!(body.contains("### Fabro Details"));
+         assert!(body.contains("Ran 3 stages in 2m 30s for $0.42"));
+@@ -1382,7 +1363,7 @@ mod tests {
+         .await
+         .unwrap();
+ 
+-        let body = build_pr_body_with_client(
++        let (_, body) = build_pr_body_with_client(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+             "Implement feature",
+             "mock-model",
+@@ -1394,8 +1375,7 @@ mod tests {
+             ),
+         )
+         .await
+-        .unwrap()
+-        .body;
++        .unwrap();
+ 
+         assert!(body.contains("Narrative from mock."));
+         assert!(body.contains("### Retro"));
+@@ -1473,7 +1453,7 @@ mod tests {
+         .await
+         .unwrap();
+ 
+-        let body = build_pr_body_with_client(
++        let (_, body) = build_pr_body_with_client(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+             "Implement feature",
+             "mock-model",
+@@ -1485,8 +1465,7 @@ mod tests {
+             ),
+         )
+         .await
+-        .unwrap()
+-        .body;
++        .unwrap();
+ 
+         assert!(body.contains("<summary>Full plan</summary>"));
+         assert!(body.contains("Plan from store"));
+@@ -1496,7 +1475,7 @@ mod tests {
+     async fn build_pr_body_uses_explicit_llm_client() {
+         let store = test_store();
+         let run_store = store.create_run(&fixtures::RUN_1).await.unwrap();
+-        let body = build_pr_body_with_client(
++        let (_, body) = build_pr_body_with_client(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+             "Implement feature",
+             "gpt-5.4",
+@@ -1508,8 +1487,7 @@ mod tests {
+             ),
+         )
+         .await
+-        .unwrap()
+-        .body;
++        .unwrap();
+ 
+         assert!(body.contains("Narrative from explicit client."));
+         assert!(!body.contains("Narrative from mock."));
+@@ -1556,7 +1534,7 @@ mod tests {
+         let run_store = store.create_run(&fixtures::RUN_1).await.unwrap();
+         let run_store_handle: RunStoreHandle = run_store.into();
+ 
+-        let pr = build_pr_body(
++        let (title, body) = build_pr_body(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+             "Implement feature",
+             "gpt-5.4",
+@@ -1567,8 +1545,8 @@ mod tests {
+         .await
+         .unwrap();
+ 
+-        assert_eq!(pr.title, "Vault title");
+-        assert!(pr.body.contains("Narrative from vault source."));
++        assert_eq!(title, "Vault title");
++        assert!(body.contains("Narrative from vault source."));
+         response_mock.assert_async().await;
+     }
+ 
+@@ -1789,7 +1767,7 @@ mod tests {
+         let run_store = store.create_run(&fixtures::RUN_1).await.unwrap();
+         let long_title = "x".repeat(200);
+         let payload = pr_content_json(&long_title, "Body content.");
+-        let title = build_pr_body_with_client(
++        let (title, _) = build_pr_body_with_client(
+             "diff --git a/src/lib.rs b/src/lib.rs\n+fn x() {}\n",
+             "Implement feature",
+             "mock-model",
+@@ -1798,14 +1776,15 @@ mod tests {
+             explicit_client("mock", &payload),
+         )
+         .await
+-        .unwrap()
+-        .title;
++        .unwrap();
+ 
+         assert_eq!(title.chars().count(), 72);
+         assert!(title.ends_with('\u{2026}'));
+     }
+ 
+-    /// Schema rejects truly empty bodies via `minLength: 1`.
++    /// Empty bodies are fatal. Real providers may reject this via the
++    /// schema's `minLength`; the Rust-side trim check also catches it for
++    /// local/mock providers.
+     #[tokio::test]
+     async fn build_pr_body_returns_err_when_body_empty() {
+         let store = test_store();
+@@ -1856,20 +1835,33 @@ mod tests {
+         // Held to keep the mock listener alive for the duration of the test;
+         // the test interacts with it via `Client::from_source` (which goes
+         // out via HTTP to the mock URL stored in `llm_source`).
+-        _openai_server: MockServer,
++        openai_server:  MockServer,
+         github_server:  MockServer,
++        openai_mock_id: usize,
++        github_mock_id: usize,
+         llm_source:     Arc<dyn CredentialSource>,
+         creds:          fabro_github::GitHubCredentials,
+         run_store:      RunStoreHandle,
+     }
+ 
++    impl FallbackHarness {
++        async fn assert_mocks_called_once(&self) {
++            httpmock::Mock::new(self.openai_mock_id, &self.openai_server)
++                .assert_async()
++                .await;
++            httpmock::Mock::new(self.github_mock_id, &self.github_server)
++                .assert_async()
++                .await;
++        }
++    }
++
+     /// Stand up an OpenAI mock that returns the given structured-output
+     /// payload, a GitHub mock that accepts a PR creation, a vault-backed
+     /// credential source, and a run store seeded with a non-empty
+     /// `final_patch`.
+     async fn setup_fallback_test_harness(openai_payload_text: &str) -> FallbackHarness {
+         let openai_server = MockServer::start_async().await;
+-        openai_server
++        let openai_mock = openai_server
+             .mock_async(|when, then| {
+                 when.method(POST)
+                     .path("/v1/responses")
+@@ -1881,7 +1873,7 @@ mod tests {
+             .await;
+ 
+         let github_server = MockServer::start_async().await;
+-        github_server
++        let github_mock = github_server
+             .mock_async(|when, then| {
+                 when.method(POST)
+                     .path("/repos/owner/repo/pulls")
+@@ -1971,10 +1963,15 @@ mod tests {
+         .await
+         .unwrap();
+ 
++        let openai_mock_id = openai_mock.id;
++        let github_mock_id = github_mock.id;
++
+         FallbackHarness {
+             _vault_dir: vault_dir,
+-            _openai_server: openai_server,
++            openai_server,
+             github_server,
++            openai_mock_id,
++            github_mock_id,
+             llm_source,
+             creds,
+             run_store: run_store.into(),
+@@ -2012,6 +2009,7 @@ mod tests {
+ 
+         let record = result.expect("PR record should be Some");
+         assert_eq!(record.title, "Fix telemetry leak");
++        harness.assert_mocks_called_once().await;
+     }
+ 
+     /// LLM returns an empty title; the fallback path produces a long title
+@@ -2050,5 +2048,6 @@ mod tests {
+         let record = result.expect("PR record should be Some");
+         assert_eq!(record.title.chars().count(), 72);
+         assert!(record.title.ends_with('\u{2026}'));
++        harness.assert_mocks_called_once().await;
+     }
+ }
+diff --git a/lib/crates/fabro-workflow/tests/it/integration.rs b/lib/crates/fabro-workflow/tests/it/integration.rs
+index 2574ee17..742218c1 100644
+--- a/lib/crates/fabro-workflow/tests/it/integration.rs
++++ b/lib/crates/fabro-workflow/tests/it/integration.rs
+@@ -6896,7 +6896,7 @@ async fn workflow_run_with_vault_only_openai_codex_builds_pr_body() {
+     let run_store = store.open_run_reader(&run_options.run_id).await.unwrap();
+     let run_store_handle: fabro_workflow::runtime_store::RunStoreHandle = run_store.into();
+ 
+-    let pr = fabro_workflow::pull_request::build_pr_body(
++    let (title, body) = fabro_workflow::pull_request::build_pr_body(
+         "diff --git a/src/lib.rs b/src/lib.rs\n+fn new_feature() {}\n",
+         "Implement feature",
+         "gpt-5.4",
+@@ -6916,8 +6916,8 @@ async fn workflow_run_with_vault_only_openai_codex_builds_pr_body() {
+     .await
+     .expect("PR body should build from vault-only credentials");
+ 
+-    assert_eq!(pr.title, "Vault title");
+-    assert!(pr.body.contains("Narrative from vault source."));
++    assert_eq!(title, "Vault title");
++    assert!(body.contains("Narrative from vault source."));
+     response_mock.assert_async().await;
+ }
+ 

stages/007-simplify_gpt@1/status.json

@@ -0,0 +1,6 @@
+{
+  "outcome": "succeeded",
+  "notes": "Stage completed: simplify_gpt",
+  "failure_reason": null,
+  "timestamp": "2026-05-04T19:15:07.168752Z"
+}

stages/008-verify@1/script_invocation.json

@@ -0,0 +1,5 @@
+{
+  "script": "cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1 && cargo nextest run --cargo-quiet --workspace --status-level fail 2>&1 && cargo dev docs refresh 2>&1 && cargo dev docs check 2>&1",
+  "command": "cargo +nightly-2026-04-14 clippy -q --workspace --all-targets -- -D warnings 2>&1 && cargo nextest run --cargo-quiet --workspace --status-level fail 2>&1 && cargo dev docs refresh 2>&1 && cargo dev docs check 2>&1",
+  "language": "shell"
+}