Bug Description

When a browser operation times out, the session is saved with an orphaned tool_use block (no matching tool_result). On next API call, this causes:

unexpected tool_use_id in tool_result blocks

Root Cause

repairToolUseResultPairing() in session-transcript-repair.ts exists but is only called during context sanitization before API calls, not when sessions are loaded from disk.

Steps to Reproduce

1. Start a session
2. Trigger a browser operation that times out (e.g., screenshot with slow page)
3. Session saves with orphaned tool_use block
4. Next API call fails with "unexpected tool_use_id" error

Suggested Fix

Call repairToolUseResultPairing() when loading sessions from disk in session-utils.fs.js:

// In readSessionMessages(), before return:
import { repairToolUseResultPairing } from "../agents/session-transcript-repair.js";

// ... existing code ...

const repaired = repairToolUseResultPairing(messages);
return repaired.messages;

Affected Files

• src/gateway/session-utils.fs.ts - session loading (needs fix)
• src/agents/session-transcript-repair.ts - repair function (already exists)
• src/agents/pi-extensions/transcript-sanitize.ts - only called on context build

Workaround

Manually patch dist/gateway/session-utils.fs.js to call repair on load (verified working).