Investigate Claude Code 'No onPostToolUseHook found' errors

[AlephNotation]

Description

When running Claude Code via ACP, we see stderr errors like:

No onPostToolUseHook found for tool use ID: toolu_01Ht5FNvuB6pcB4khEHziUJp

These errors occur for TodoWrite tool calls (Claude Code's internal task tracking tool).

Current Workaround

We're filtering out these errors in src/agents/agent-runner.ts since they appear to be benign - the tool still works correctly.

Investigation Needed

1. Is this a Claude Code bug in ACP mode?
2. Should we report this upstream to claude-code?
3. Are there other internal tools that might have similar issues?

Related Code

• Filter added in: src/agents/agent-runner.ts:handleAgentStderr()
• Tool affected: TodoWrite (Claude Code internal)