fact-check-before-trust

name	fact-check-before-trust
version	1.0
category	core
description	Triggers a secondary verification pass for any agent output containing factual claims, numbers, dates, or named entities before the output is acted on

fact-check-before-trust

verification-before-completion checks that a task was done. This skill checks that the facts are correct. An agent confidently reporting a £716 visa fee as £70,000 will pass completion verification — this skill catches it.

When to invoke

Invoke this skill before treating any agent output as authoritative when the output contains:

• Numbers or money (prices, quantities, measurements, statistics)
• Dates and deadlines (filing deadlines, release dates, expiry dates)
• Named entities (people, organisations, laws, product names)
• Causal claims ("X causes Y", "because of Z")
• Superlatives ("the largest", "the only", "the most recent")

Skip for: code output, file system operations, and clearly self-contained tasks (renaming a variable, formatting a document).

Verification protocol

Step 1 — Extract claims Identify every verifiable claim in the output. List them explicitly:

Claim 1: UK visa fee is £716
Claim 2: Processing time is 3 weeks
Claim 3: Applies to Tier 2 (Skilled Worker) visa category

Step 2 — Score each claim For each claim, assign a confidence level:

• High — Agent has direct evidence in its context (read a document, fetched a URL)
• Medium — Agent inferred from training data (check recency)
• Low — Agent stated without citing a source

Step 3 — Verify low/medium claims For each Low or Medium claim:

1. Search or re-fetch the source if possible
2. If source found: update confidence to High or mark Contradicted
3. If no source available: mark Unverifiable

Step 4 — Classify output

Result	Meaning
✓ Verified	All claims High confidence
⚠ Uncertain	1+ Unverifiable claims
✗ Contradicted	1+ claims conflict with found evidence

Step 5 — Surface to user

• Verified: proceed
• Uncertain: surface unverifiable claims with a note
• Contradicted: stop, show the contradiction, do not use the output until resolved

Difference from verification-before-completion

verification-before-completion checks: "Did the agent do the task?" (task completion) fact-check-before-trust checks: "Is what the agent said true?" (output accuracy)

Both should be used for research, financial, legal, and compliance workflows.