review: orchestrator on Sonnet 5 at low effort

.changeset/review-sonnet-low-orchestrator.md

@@ -0,0 +1,5 @@
+---
+"review": minor
+---
+
+The orchestrator moves to Claude Sonnet 5 at low reasoning effort (`engine.model: claude-sonnet-5` plus `CLAUDE_CODE_EFFORT_LEVEL: low` in the engine env). With task mode removed the orchestrator's job is transcription plus a handful of small judgments (thread staging, the router tier questions, Steps 7-8), the dispatch-conformance gate turns any transcription drift into a red run rather than a wrong review, and the lifecycle trial measured the orchestrator line at $2.0-3.1/run on Opus, the largest non-reviewer cost; Sonnet at roughly 40% of Opus pricing with a low-effort dial cuts most of it while keeping near-Opus instruction-following. Sub-agents are untouched: they pin their own models, and the dispatcher's runner strips `CLAUDE_CODE_EFFORT_LEVEL` from the sub-agent environment so the reviewer roles can never silently inherit the orchestrator's effort dial. The pinned firewall (gh-aw-firewall v0.27.27) already prices `claude-sonnet-5`; a `models:` entry keeps gh-aw's cost display correct. Live-trial-gated: the seeded lifecycle that validates the scripted-only pin runs this branch as its second arm against an Opus-orchestrator control.

workflows/review/README.md

@@ -342,7 +342,7 @@ sub-agent models — this table is the human-facing summary:
 
 | Role | Model | Effort | Why |
 | --- | --- | --- | --- |
-| orchestrator | `claude-opus-4-8` | high | Owns every GitHub/safe-output decision |
+| orchestrator | `claude-sonnet-5` | low | Transcribes the plan and stages threads; the gate reds any transcription drift, and the reasoning lives in the sub-agents (the runner strips the orchestrator's effort env from theirs) |
 | `pattern-triage` | `claude-sonnet-4-6` | medium | Cheap first-pass triage |
 | `thread-reconciler` | `claude-opus-4-8` | medium | Reconciliation |
 | `correctness-reviewer` | `claude-fable-5` | high | Whole-change reviewer; bug-finding recall is the load-bearing metric |

workflows/review/lib/dispatch-runner.ts

@@ -11,6 +11,27 @@
 
 import type {AgentRequest, AgentResult, AgentRunner} from "./dispatch";
 
+/**
+ * The environment the sub-agents run under: the sandbox env minus the
+ * orchestrator's effort dial. The engine sets CLAUDE_CODE_EFFORT_LEVEL for
+ * the ORCHESTRATOR (Sonnet at low effort), and env vars reach every process
+ * in the sandbox — without this filter the SDK-spawned reviewers would
+ * silently inherit low effort too, degrading the reasoning roles the
+ * orchestrator dial was never meant to touch. Sub-agents keep the harness
+ * default (their definitions' effort annotations remain the human-facing
+ * table in the README until gh-aw grows a per-agent effort field).
+ */
+export const subAgentEnv = (
+    env: Record<string, string | undefined>,
+): Record<string, string> =>
+    Object.fromEntries(
+        Object.entries(env).filter(
+            (entry): entry is [string, string] =>
+                entry[1] !== undefined &&
+                entry[0] !== "CLAUDE_CODE_EFFORT_LEVEL",
+        ),
+    );
+
 /**
  * Build the production runner. The SDK and zod are imported lazily here
  * (both installed by the scripted-mode `npm ci` pre-agent step); zod is the
@@ -57,6 +78,7 @@ export const createSdkRunner = async (): Promise<AgentRunner> => {
             allowedTools,
             permissionMode: "bypassPermissions",
             abortController: abort,
+            env: subAgentEnv(process.env),
         };
         // The structured-final channel (trial suggestion h): an in-process
         // MCP tool whose handler runs the same contract parse the collection

workflows/review/lib/dispatch-trial-followups.test.ts

@@ -7,6 +7,7 @@ import {
     type DispatchFs,
 } from "./dispatch";
 import {computeDiffProvenance} from "./provenance";
+import {subAgentEnv} from "./dispatch-runner";
 
 /**
  * Post-trial follow-up tests for the scripted dispatcher: the
@@ -322,3 +323,15 @@ describe("open-thread suppression (trial suggestion g)", () => {
         expect(result.claims).toHaveLength(1);
     });
 });
+
+describe("subAgentEnv (the orchestrator effort dial never reaches sub-agents)", () => {
+    it("strips CLAUDE_CODE_EFFORT_LEVEL and undefined values, keeps the rest", () => {
+        expect(
+            subAgentEnv({
+                CLAUDE_CODE_EFFORT_LEVEL: "low",
+                REVIEW_REPO_ROOT: "/work",
+                EMPTY: undefined,
+            }),
+        ).toEqual({REVIEW_REPO_ROOT: "/work"});
+    });
+});

workflows/review/review.md

@@ -167,20 +167,34 @@ observability:
         headers:
           x-sentry-auth: ${{ secrets.GH_AW_OTEL_SENTRY_AUTHORIZATION }}
 
-# Pin the orchestrator to a specific model version rather than a floating tier alias, so
-# the review doesn't silently change behavior when a new Opus ships. If we use Opus, we
-# use Opus 4.8. Sub-agents pin their own versions in their frontmatter below.
+# Pin the orchestrator to a specific model version rather than a floating tier
+# alias, so the review doesn't silently change behavior when a new model ships.
+# Sub-agents pin their own versions in their frontmatter below; the reasoning
+# stays on their models (Fable/Opus). The orchestrator itself is Sonnet at LOW
+# effort: with task mode removed its job is transcription plus a handful of
+# small judgments (thread staging, the tier questions, Steps 7-8), the
+# dispatch-conformance gate turns any transcription drift into a red run
+# rather than a wrong review, and the trial measured the orchestrator line at
+# $2-3/run on Opus — the single largest non-reviewer cost. claude-sonnet-5 is
+# its own pin (Sonnet 5 has no dated alias).
 #
-# The `env:` overrides gh-aw's 60s Bash tool timeout defaults (compile-verified:
-# these replace the generated values on the engine execution step). Needed by the
-# scripted dispatch mode (ROUTING `dispatch scripted`): the orchestrator invokes
-# the deterministic dispatcher (lib/dispatch.ts) as ONE blocking Bash call that
-# waits for the whole sub-agent fan-out, which takes minutes, not seconds. The
-# job-level timeout-minutes still bounds the run.
+# CLAUDE_CODE_EFFORT_LEVEL sets the orchestrator's reasoning effort (it
+# outranks the CLI flag and settings.json). It reaches the whole sandbox env,
+# so the dispatcher's runner (lib/dispatch-runner.ts) strips it from the
+# sub-agent environment — reviewer effort must never silently follow the
+# orchestrator dial.
+#
+# The BASH_* env overrides replace gh-aw's 60s Bash tool timeout defaults
+# (compile-verified: these replace the generated values on the engine
+# execution step). Needed because the orchestrator invokes the deterministic
+# dispatcher (lib/dispatch.ts) as ONE blocking Bash call that waits for the
+# whole sub-agent fan-out, which takes minutes, not seconds. The job-level
+# timeout-minutes still bounds the run.
 engine:
   id: claude
-  model: claude-opus-4-8
+  model: claude-sonnet-5
   env:
+    CLAUDE_CODE_EFFORT_LEVEL: "low"
     BASH_DEFAULT_TIMEOUT_MS: "60000"
     BASH_MAX_TIMEOUT_MS: "1200000"
 timeout-minutes: 20
@@ -217,6 +231,15 @@ models:
             output: 5.0e-05
             cache_read: 1.0e-06
             cache_write: 1.25e-05
+        # The orchestrator's model (same caveat: keeps gh-aw's cost display
+        # correct; the firewall api-proxy's own table, v0.27.27, already
+        # prices it).
+        claude-sonnet-5:
+          cost:
+            input: 3.0e-06
+            output: 1.5e-05
+            cache_read: 3.0e-07
+            cache_write: 3.75e-06
 
 # The shared review workflow is more than this markdown file: its deterministic
 # pieces (the finding schema and validator today; the router, computed verdict, and