chore: ACP SDK rejects usage_update notifications from claude-agent-acp

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
68/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
typescript
Domain
backend, testing-qa

Research direction

Start in apps/workers/coder-acp-claude-code and inspect the dependency declaration and notification handling, then read claude-code.integration.test.ts to reproduce the logged validation error. Done means usage_update notifications no longer produce non-fatal Error handling notification messages and the integration test still passes.

Written by the indexing model from the issue text.

Description

author: cedricvidal

Original author: @cedricvidal

Summary

The Claude Code ACP worker (and its integration test) logs noisy Error handling notification messages for usage_update session notifications. The test still passes — these are non-fatal — but the errors clutter logs and may mask real issues.

Error

Error handling notification {
  jsonrpc: '2.0',
  method: 'session/update',
  params: {
    sessionId: '...',
    update: { sessionUpdate: 'usage_update', used: 16690, size: 200000 }
  }
} {
  code: -32602,
  message: 'Invalid params',
  data: {
    _errors: [
      'Invalid input: expected object, received undefined',
      ...
    ]
  }
}

Root Cause

The usage_update notification is a newer ACP protocol feature sent by claude-agent-acp@0.29.1. The pinned @agentclientprotocol/sdk@0.13.1 doesn't have a schema for this notification type, so its JSON-RPC validation layer rejects the shape before it reaches the sessionUpdate handler's default: break; case.

Affected Components

  • apps/workers/coder-acp-claude-code (production worker)
  • Integration test (claude-code.integration.test.ts)

Fix Options

  1. Bump @agentclientprotocol/sdk to a version that includes the usage_update schema (preferred)
  2. Suppress the error by adding a try/catch or custom notification handler at the SDK level (workaround)

Environment

  • @agentclientprotocol/claude-agent-acp: 0.29.1
  • @agentclientprotocol/sdk: 0.13.1
Dominant language
TypeScript
Stars
4
Forks
1
Avg merge
5d 7h
Merged PRs (30d)
10

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