flake: TestAgent_DevcontainersDisabledForSubAgent

[flake-investigator]

CI Run Link: https://github.com/coder/coder/actions/runs/23870054791
Failing Job: https://github.com/coder/coder/actions/runs/23870054791/job/69599437690 (test-go-race-pg)
Commit: 3a4a0b7270436e58ad6aa9a03a242c73f73bd388 (Ben Potter) coder/coder@3a4a0b7

Failure summary:

• TestAgent_DevcontainersDisabledForSubAgent failed in package agent.
• Log evidence shows the containers API returning 403 during the test:
  • agent: GET ... /api/v0/containers ... status_code=403
• No explicit assertion output (Error Trace) appeared in the job logs beyond the 403 response; likely mismatch in expected error text or response detail.

Error evidence:

agent: GET ... /api/v0/containers ... status_code=403

Root cause classification: Flaky test / unexpected error response (insufficient log detail to determine exact assertion mismatch).

Precise assignment analysis:

• git blame -L 2512,2534 agent/agent_test.go => last change to this test in commit 0118e750 (Danielle Maywood) “fix(agent): disable dev container integration inside sub agents”.
• Component context: devcontainer sub-agent handling in agent/api.go / agent/agentcontainers is owned by Danielle Maywood.

Related issues search (coder/internal):

• "TestAgent_DevcontainersDisabledForSubAgent"
• "Dev Container feature not supported"
• "devcontainer sub agent"
  No direct duplicates found.

Reproduction (best effort):

• go test ./agent -run TestAgent_DevcontainersDisabledForSubAgent -count=50