Missing Tool Call

Detector key: missing_tool_call · Source: coordination · Severity: high · Suspicion: 80

Some requests require a side effect. “Book it”, “refund me”, “send the email” — these can’t be satisfied by talking, only by calling a tool. This detector fires when the user asked for such an action, the agent claimed success, but no tool step ever ran. The most likely truth: nothing happened.

What trips it

All three conditions must hold:

1. The request contains an action verb — matched as a whole word in userRequestText: book, refund, schedule, cancel, send, update, create, delete, pay, charge, transfer, reschedule, reserve, order, submit, register, subscribe, unsubscribe, issue.
2. No tool step ran in the entire run — if any tool fired, the detector stays quiet (the action isn’t obviously missing).
3. The agent claimed success — the run’s success flag or completion language in the final output.

Whole-word matching

Verbs match on word boundaries, so “issue” won’t match “tissue” or “issues”. This keeps the detector conservative.

Score

Fixed at 80.

Example

trips missing_tool_call

{
  "userRequestText": "Please cancel my subscription.",
  "success": true,
  "outcomeSummary": "Done — your subscription has been cancelled.",
  "steps": [
    { "stepKind": "model", "outputSummary": "Done — your subscription has been cancelled." }
  ]
}

Lumni reports:

Missing action: agent claimed to “cancel” but called no tool — The user asked the agent to “cancel”, the agent claimed success (“Done — your subscription has been cancelled.”), but no tool/action step ever executed. The side effect almost certainly never happened.

Why it matters

This is the coordination failure behind dropped sub-agent hand-offs and over-eager assistants that “confirm” an action they never performed. It’s especially common in support-tool agents that reply in natural language without a recorded action.