fix(mothership): start no tool call with less than a minute of its deadline left

[waleedlatif1]

Summary

• A call whose deadline was nearly spent could still start: an approval granted seconds before the deadline, a workflow server fallback, or a client pickup would launch a handler that the deadline then abandoned with its outcome unknown. That is a real side-effect risk once the worker stamps deadlines on every call.
• One shared minimum start budget, SIM_TOOL_MIN_START_BUDGET_MS = 60 s. It is the same constant takeover re-runs already used, now renamed for both.
• Every start point refuses to start a call with less than that left, through toolStartWindowClosed / lastToolStartAt in deadline.ts:
  • the executor
  • opening and honoring an approval (the prompt wait now ends at the last start time)
  • the workflow server fallback
  • client pickup
• The same window is enforced where a late client would start the call: claimWorkflowToolExecution and claimDesktopToolCall refuse a call whose saved deadline leaves less than the budget, and a client call nothing claimed by its deadline is settled as not run rather than outcome unknown.
• A refused call is settled durably as "did not run". The executor commits the failure; a client call nothing claimed takes the unclaimed-only settlement.
• Why 60 s: about 99% of non-workflow tool calls finish within a minute (p90 ≈ 7 s, p99 ≈ 82 s), so a call that starts with at least that much left almost always finishes.
• Calls without a deadline behave exactly as before.

Release order

1. This PR must be in a Sim release before the worker PR that stamps deadlineMs on handed frames (simstudioai/mothership#706) reaches prod.

Type of Change

• Bug fix

Testing

Each new test fails on staging and passes here:

• executor.test.ts: a handler with 30 s of its deadline left is not started
• permission.test.ts: an approval granted with under a minute left is not honored
• workflow-client-fallback.test.ts: no server takeover with under a minute left
• handlers.test.ts: an unclaimed client call with under a minute left is settled as not run without being offered; one nothing claimed by its deadline is settled as not run
• abandoned-runs.integration.ts / desktop-tool-authorization.integration.ts: browser and desktop claims are refused with under a minute left

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 15, 2026 11:19pm UTC

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The changes since the previous review introduce no new blocking issue.

Summary

This PR requires at least one minute remaining before a tool call starts.

• Deadline-bound tool calls start only when at least a minute remains.

No new actionable findings were identified in the changes since the previous review. Tests were inspected, not run.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Tool call] --> B{Deadline present?}
  B -->|No| C[Existing start rules]
  B -->|Yes| D{At least one minute left?}
  D -->|Yes| E[Check permission and ownership]
  E --> F[Start work]
  D -->|No| G[Refuse new start]

Loading

_{Reviews (2) · Last reviewed commit: "fix(mothership): refuse a late claim at ..." · Reviewed by Greptile}

[cubic-dev-ai]

All reported issues were addressed across 11 files

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[waleedlatif1]

@greptileai review

[waleedlatif1]

@cubic-dev-ai review

[cubic-dev-ai]

@cubic-dev-ai review

@waleedlatif1 I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

All reported issues were addressed across 13 files

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>