Check reference
Checks are pure detectors that run before (input) or after (output) a call. Each returns a finding.
| Check | Phase | What it detects |
|---|---|---|
| timeout | post | Upstream exceeded its timeout. |
| transport_error | post | Network error, 5xx, or MCP isError. |
| rate_limited | post | HTTP 429 or rate-limit text; parses Retry-After. |
| auth_error | post | 401/403 or expired token. Alerts the owner. |
| empty_result | post | Null, empty, or unusually short output. |
| partial_result | post | Truncation markers or missing required fields. |
| schema_drift | post | Output shape differs from the stored snapshot. |
| input_schema_violation | pre | Args fail the tool's JSON Schema. |
| amount_sanity | pre | Amount is non-positive, huge, or 10x historical p95. |
| contradiction | pre/post | Refund over order total, currency or recipient mismatch. |
| duplicate_action | pre | Same key fields within a window. |
| error_in_success | post | 200/ok body that contains error words. |
| loop_detect | pre | Same tool + input repeated; tells the agent to stop. |
| hallucinated_id | pre | An id argument never seen earlier in the session. |
| pii_outbound | pre | Card, Aadhaar, PAN, or another customer's contact in a message. |
| consistency_drift | async | Same input, divergent outcomes across runs. |
| llm_judge | async | Optional BYO-key judge of plausibility. |