From cf269289e4bbdd9e0f70c12adb3cedcd178562be Mon Sep 17 00:00:00 2001
From: Merge Sim <sim@local>
Date: Wed, 2 Sep 2026 12:59:48 -0700
Subject: [PATCH] fix(agents): preserve canonical coverage provenance

---
 .../pane-agent-identity-adapter.test.ts       | 20 +++++++++++++++-
 src/shared/pane-agent-identity-adapter.ts     | 23 +++++++++++++++----
 ...ublished-pane-agent-identity-comparison.ts | 10 ++++++--
 3 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/src/shared/pane-agent-identity-adapter.test.ts b/src/shared/pane-agent-identity-adapter.test.ts
index 883ab4675f5..ea52fe50477 100644
--- a/src/shared/pane-agent-identity-adapter.test.ts
+++ b/src/shared/pane-agent-identity-adapter.test.ts
@@ -120,6 +120,19 @@ describe('uncovered compatibility lane', () => {
     })
     expect(identity).toMatchObject({ agent: null, source: null, coverage: 'uncovered' })
   })
+
+  it('does not label a foreground-only compatibility answer as title-only', () => {
+    const identity = resolveCanonicalPaneAgentIdentity({
+      foregroundAgent: 'codex',
+      uncoveredFallback: { agent: 'codex' }
+    })
+    expect(identity).toMatchObject({
+      agent: 'codex',
+      source: null,
+      coverage: 'uncovered',
+      titleOnly: false
+    })
+  })
 })
 
 describe('canonical ladder inside the covered lane', () => {
@@ -178,7 +191,12 @@ describe('reclaim-versus-stale-hook discriminator (run keys, not title text)', (
       currentRun: run2,
       title: 'STA-4011 Linux Antigravity Commit Messages - grok'
     })
-    expect(identity).toMatchObject({ agent: 'grok', source: 'title' })
+    expect(identity).toMatchObject({
+      agent: 'grok',
+      source: 'title',
+      coverage: 'uncovered',
+      titleOnly: true
+    })
     expect(identity.supersededSources).toEqual(['completed-hook'])
   })
 
diff --git a/src/shared/pane-agent-identity-adapter.ts b/src/shared/pane-agent-identity-adapter.ts
index c9508c83e63..6562f5f551d 100644
--- a/src/shared/pane-agent-identity-adapter.ts
+++ b/src/shared/pane-agent-identity-adapter.ts
@@ -145,9 +145,24 @@ export function resolveCanonicalPaneAgentIdentity(
   input: CanonicalPaneAgentIdentityInput
 ): CanonicalPaneAgentIdentity {
   const processEvidence = processEvidenceFromProof(input)
-  // Coverage comes from authority-bearing sources only: hook, proven process, launch, sleeping
-  // session. A bare foreground name, a sibling, and a title never cover a pane.
+  // Coverage comes from authority-bearing sources that are still eligible for this run. A stale
+  // hook/launch row can remain in the input after a pane is replaced; it must not make a title-only
+  // answer look covered to a future action consumer.
+  const runIsEligible = (run: PaneAgentRunKey | undefined): boolean =>
+    run === undefined ||
+    input.currentRun === undefined ||
+    run.authorityId !== input.currentRun.authorityId ||
+    run.incarnation === input.currentRun.incarnation
   const covered = Boolean(
+    (input.hookAgent && runIsEligible(input.hookRun)) ||
+    (input.completedHookAgent && runIsEligible(input.completedHookRun)) ||
+    processEvidence ||
+    (input.launchAgent && runIsEligible(input.launchRun)) ||
+    (input.sleepingSessionAgent && runIsEligible(input.sleepingRun))
+  )
+  // Keep stale evidence in the resolver so diagnostics still report which source was superseded,
+  // even when it no longer qualifies the pane as covered.
+  const hasAuthorityEvidence = Boolean(
     input.hookAgent ||
     input.completedHookAgent ||
     processEvidence ||
@@ -156,7 +171,7 @@ export function resolveCanonicalPaneAgentIdentity(
   )
   const titleAgent = input.title ? collectAgentTitleEvidence(input.title).agent : null
 
-  if (!covered) {
+  if (!hasAuthorityEvidence) {
     if (input.uncoveredFallback) {
       const agent = input.uncoveredFallback.agent
       const titleOnly =
@@ -227,7 +242,7 @@ export function resolveCanonicalPaneAgentIdentity(
   return {
     agent: resolved.agent,
     source: resolved.source,
-    coverage: 'covered',
+    coverage: covered ? 'covered' : 'uncovered',
     titleOnly: resolved.source === 'title',
     ...(resolved.ambiguousAt ? { ambiguousAt: resolved.ambiguousAt } : {}),
     supersededSources: resolved.supersededSources
diff --git a/src/shared/published-pane-agent-identity-comparison.ts b/src/shared/published-pane-agent-identity-comparison.ts
index 91f1c27d8aa..c5cd0a3f990 100644
--- a/src/shared/published-pane-agent-identity-comparison.ts
+++ b/src/shared/published-pane-agent-identity-comparison.ts
@@ -65,15 +65,21 @@ function recordCanonicalDivergence(
   }
   // No host process PROOF exists yet, so the canonical lane sees the foreground name as a weak
   // hint only. Where that alone flips the answer is precisely what this window measures.
+  const titleAgent = args.title ? collectAgentTitleEvidence(args.title).agent : null
   const canonical = resolveCanonicalPaneAgentIdentity({
     hookAgent: args.hookAgent,
     hookIsLive: args.hookIsLive,
     launchAgent: args.launchAgent,
     foregroundAgent: args.foregroundAgent,
     title: args.title,
-    uncoveredFallback: { agent: published, titleOnly: published !== null }
+    uncoveredFallback: {
+      agent: published,
+      // A bare foreground name is an uncovered compatibility answer, but it is not title proof.
+      // Mark title-only only when no foreground signal exists and the frozen answer matches title
+      // evidence exactly.
+      titleOnly: args.foregroundAgent == null && published !== null && published === titleAgent
+    }
   })
-  const titleAgent = args.title ? collectAgentTitleEvidence(args.title).agent : null
   recorder.record({
     surface: args.surface,
     paneId: args.paneId,