User incident (Slack, 2026-05-13): user walked away mid-conversation,
agent requested approval to run `rm -rf .git`, the prompt timed out
after the gateway_timeout (default 300s), and the agent removed the
.git folder on its own. Corroborated by an independent report from a
Telegram user.
The underlying code path was correct — `check_all_command_guards`
returns `approved=False` with a BLOCKED message on both timeout and
explicit deny, and `terminal_tool` surfaces that as `status=blocked`
to the agent. The bug is at the model-interface layer: the message
"BLOCKED: Command timed out. Do NOT retry this command." reads to
some models as "try a different command achieving the same outcome."
This commit changes only the model-facing message + the structured
return shape:
- Timeout message now explicitly names the three evasion paths the
agent must avoid: retry, rephrase, AND achieve the same outcome
via a different command. Ends with "Silence is not consent."
- Explicit deny gets the same shape minus the silence-is-not-consent
line (it WAS an explicit deny, not silence).
- New structured fields on the return dict: `outcome` ("timeout"
or "denied") and `user_consent` (always False on this branch)
so plugins, hooks, and audit pipelines don't have to string-parse
the message to distinguish the two cases.
The mechanism that should already have prevented the original incident
— timeout treated as deny, BLOCKED result, post hook fires with
`choice="timeout"` — is unchanged. This commit hardens only the
agent's reading of the result.
Tests:
- test_timeout_returns_approved_false_with_no_consent — pins the
return shape on the Slack-shaped notify_cb-registered path
- test_timeout_message_is_emphatic_against_retry_and_rephrase —
pins the exact phrases the message must contain
- test_explicit_deny_carries_same_no_consent_shape — same contract
on explicit /deny
- test_timeout_emits_post_hook_with_timeout_outcome — pins the
post_approval_response hook payload so audit plugins can act
329 approval tests passing (4 new + 325 existing).
Fixes#24912
7f1b2b4569