Summary

installOpenRouterDebugFetch reassigns globalThis.fetch for the duration of a run and restores it blindly in a finally. If two runOpenWikiAgent calls overlap in the same process, their install/restore steps corrupt each other — the wrapper can leak permanently or be lost. It also only captures error bodies for OpenRouter, leaving Anthropic/OpenAI/Bedrock 4xx/5xx bodies invisible to classifyError.

Details

// src/agent/index.ts:1399-1452
function installOpenRouterDebugFetch(
  options: OpenWikiRunOptions,
): OpenRouterFetchCapture {
  const originalFetch = globalThis.fetch;
  // ...
  globalThis.fetch = (async (input, init) => { /* ... */ }) satisfies typeof fetch;

  return {
    // ...
    restore: () => {
      globalThis.fetch = originalFetch;
    },
  };
}

Failure mode with overlapping runs (subagents, tests running in parallel, a long-lived host process):

1. Run A installs, capturing the real fetch as originalFetch.
2. Run B installs, capturing A's patched fetch as its "original."
3. Run A finishes and restores the real fetch.
4. Run B finishes and restores A's patched fetch — now leaked into the global forever.

Depending on interleaving, the patch can also be lost mid-run.

Suggested fix

Attach diagnostics per-model via the provider client's configuration.fetch hook — the same mechanism already used for Codex and Vertex (src/agent/index.ts:710,853) — instead of a process-global swap. This removes the concurrency hazard and generalizes error-body capture to every provider, not just OpenRouter.

If a global swap must be retained short-term, guard it with a reentrancy counter and a stack-based restore so nested installs compose correctly.

Location

src/agent/index.ts:1399-1452