CCARF Practice Question

Paper 4 · Question 21

D2 Tool Design & MCP Integration · Paper 4

A tool returns an empty array after a customer lookup. The agent retries 3 times, then escalates to a human agent. Analysis shows the customer's account simply does not exist. What is the root cause of this wasted effort?

• A.The escalation threshold is too aggressive — the agent should exhaust more retries before involving a human.
• B.The system prompt should instruct the agent not to retry customer lookups.
• C.The tool does not distinguish between access failures and valid empty results, so the agent treats 'no matches' as a retriable failure.
• D.The retry limit is too low — increasing to 5 retries would resolve the issue.

Show answer & explanations

Correct answer: C

A: The problem is not the escalation threshold. The problem is that the agent retries at all. A valid empty result requires no retry and no escalation.

B: Hard-coding retry rules per tool in the system prompt is brittle. The proper fix is structured error metadata that tells the agent whether the result is retryable.

C: The tool successfully queried the data source and found no matches. This is a valid empty result, not an access failure. The agent's recovery logic cannot distinguish the two, causing it to retry when it should accept the result.

D: More retries make the problem worse. The tool succeeded — it found no matching customer. Retrying a successful query with no matches will never produce different results.

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