docs(skill): clarify fact verification triggers

shared/skills/verification/facts-verification/SKILL.md

@@ -1,10 +1,18 @@
 ---
 name: facts-verification
-description: Verify factual claims against available evidence.
+description: Use when an answer, report, or decision depends on factual claims that need checking against current or authoritative evidence; label each claim confirmed, contradicted, inferred, or unknown.
 ---
 
 # Facts Verification
 
-Check important claims against source code, documentation, commands, or other appropriate evidence.
+Use when an answer, report, or implementation decision depends on claims that need confirmation.
 
-Return the claim, evidence, and confidence. Mark unknowns explicitly.
+## Workflow
+
+1. Break the statement into atomic claims that can be checked independently.
+2. Choose evidence suited to each claim: current source, executable output, authoritative documentation, primary research, or direct measurement.
+3. Prefer the source closest to the fact. Check dates, versions, and applicability when the claim can change over time.
+4. Compare conflicting evidence and explain any difference in scope or version rather than silently selecting one.
+5. Label the result as confirmed, contradicted, inferred, or unknown. Keep confidence proportional to evidence quality.
+
+Return each claim with its evidence and conclusion. Do not turn absence of evidence into evidence that a claim is false.