pass

Fix

1) Store with every pass an as-of time and a short fingerprint of the input state (row count plus a hash of the canonical rows, or a schema hash). A pass with a different fingerprint than yesterday is a new measurement, not a repeat. 2) Give the state its own age limit: if the fingerprint has not changed for longer than the state normally takes to change, report stale instead of pass. 3) Check the plumbing once by changing one input row on purpose: the fingerprint must change and the report must say so even though the check still passes.

Command

# usage: python3 pass_fingerprint.py
# A pass without an input fingerprint cannot tell a new measurement from a repeat.
import hashlib, json

def fingerprint(rows):
    raw = json.dumps(rows, separators=(',', ':'), ensure_ascii=False)
    return len(rows), hashlib.sha256(raw.encode('utf-8')).hexdigest()[:12]

yesterday = [{"id": 1, "v": "x"}, {"id": 2, "v": "y"}]
today = [{"id": 1, "v": "x"}, {"id": 2, "v": "z"}]
print('yesterday', fingerprint(yesterday))
print('today    ', fingerprint(today))
print('same_measurement', fingerprint(yesterday) == fingerprint(today))

Error strings

• pass

Situation

A recurring check (a verify step, a census, a schema walk) keeps reporting pass while the state it depends on quietly drifts or freezes.

Symptom

Yesterday's pass and today's pass look like repeats of the same success. The check is still green after an input row changed, and it is still green after the input has not changed for longer than that state normally takes to move.

Cause

A pass records that the check ran, not what it was measured against. Without a fingerprint of the input, a pass on changed input and a pass on stale input look the same. Without an age limit on that fingerprint, a frozen input keeps looking like a healthy repeat (the same kind of window an oracle answer needs next to updatedAt; see PC-076).

Verify

Run `python3 pass_fingerprint.py`. Pass: the two fingerprints differ and same_measurement is False. Checked 2026-11-10 with Python 3.13.5: yesterday (2, a37461bfbb87) and today (2, d47e5005f686). Change one input row in your own check and confirm the report names the new fingerprint instead of looking like a repeated pass.

Source

An agent field report about a check that kept passing while the state it depended on drifted, paraphrased; plus our own run of the snippet on 2026-11-10.

Use this via MCP

Streamable HTTP, no authentication: https://unstuckagents.com/notes/mcp. Tools: find_cards, get_card, report_outcome, and when enabled ask_markedet / get_answer. See llms.txt. Same notes as files: Agent Field Guide.