fact-checking

Evidence-based verification of technical claims in code, docs, and comments. Extracts claims as hypotheses, triages them by risk, and verifies each against source code with traceable evidence and honest uncertainty. A core spellbook capability for catching incorrect assumptions and outdated comments before they reach production.

Auto-invocation: Your coding assistant will automatically invoke this skill when it detects a matching trigger.

Use when verifying technical claims in code, docs, or comments before merge. Triggers: 'is this claim correct', 'verify this', 'fact check', 'is this accurate', 'check these assertions', 'are these comments true'. NOT for: checking if AI hallucinated references (use dehallucination).

Skill Content

<ROLE>
Scientific Skeptic + ISO 9001 Auditor. Claims are hypotheses. Verdicts require data.
Professional reputation depends on evidence-backed conclusions. Are you sure?
</ROLE>

## Evidence Hierarchy Reference

This skill follows the shared evidence hierarchy, depth escalation protocol, and mandatory inconclusive conditions defined in `skills/shared-references/evidence-hierarchy.md`. Verification agents must cite evidence tiers in every verdict. The depth escalation protocol governs re-verification requirements.

## CoVe Self-Interrogation Reference

This skill applies the Chain-of-Verification protocol defined in `skills/shared-references/cove-protocol.md` during claim extraction (Phases 2-3). CoVe self-interrogation runs on synthesized or inferred claims to catch extraction errors before triage. See the shared reference for the full three-step protocol and fact-checking integration notes.

## Invariant Principles

1. **Claims are hypotheses** - Every claim requires empirical evidence before verdict
2. **Evidence before verdict** - No verdict without traceable, citable proof
3. **User controls scope** - User selects scope and approves all fixes
4. **Deduplicate within run** - Re-running the same fact-check on an unchanged
   scope returns the same verdicts (the `.fact-checking/state.json` checkpoint
   tracks per-claim completion; resumption checks it before re-verifying).
5. **Learn from trajectories** - Store verification trajectories in the run's
   checkpoint state for in-session resume; cross-session reuse is a future
   concern, not a current invariant.

<CRITICAL>
<ARH_INTEGRATION>
ARH response handling during triage:

| Pattern | Action |
|---------|--------|
| RESEARCH_REQUEST ("research", "check", "verify") | Dispatch research subagent |
| UNKNOWN ("don't know", "not sure") | Dispatch analysis subagent |
| CLARIFICATION (ends with ?) | Answer, then re-ask |
| SKIP ("skip", "move on") | Proceed to next item |
</ARH_INTEGRATION>
</CRITICAL>

<analysis>
Before ANY action:
- Current phase? (config/scope/extract/triage/verify/report/learn/fix)
- What EXACTLY is claimed? What proves TRUE? What proves FALSE?
- Checkpoint read from `.fact-checking/state.json` (the run's existing
  findings and completed-claim list); appropriate verification depth.
</analysis>

## Inputs/Outputs

| Input | Required | Description |
|-------|----------|-------------|
| `scope` | Yes | branch changes, uncommitted, or full repo |
| `modes` | No | Missing Facts, Extraneous Info, Clarity (default: all) |
| `autonomous` | No | Skip prompts, use defaults |

| Output | Type | Description |
|--------|------|-------------|
| `verification_report` | Inline | Summary, findings, bibliography |
| `implementation_plan` | Inline | Fixes for refuted/stale claims |
| `glossary` | Inline | Key facts (Clarity Mode) |
| `state_checkpoint` | File | `.fact-checking/state.json` |

---

## Shared Data Structures

### Verdict Table

| Verdict | Meaning | Evidence Required |
|---------|---------|-------------------|
| Verified | Claim is accurate | test output, code trace, docs, benchmark |
| Refuted | Claim is false | failing test, contradicting code |
| Incomplete | True but missing context | base verified + missing elements |
| Inconclusive | Cannot determine | document attempts, why insufficient |
| Ambiguous | Wording unclear | multiple interpretations explained |
| Misleading | Technically true, implies falsehood | what reader assumes vs reality |
| Jargon-heavy | Too technical for audience | unexplained terms, accessible version |
| Stale | Was true, no longer applies | when true, what changed, current state |
| Extraneous | Unnecessary/redundant | value analysis shows no added info |

### Bibliography Formats

| Type | Format |
|------|--------|
| Code trace | `file:lines - finding` |
| Test | `command - result` |
| Web source | `Title - URL - "excerpt"` |
| Git history | `commit/issue - finding` |
| Documentation | `Docs: source section - URL` |
| Benchmark | `Benchmark: method - results` |
| Paper/RFC | `Citation - section - URL` |

---

## Workflow

### Phase 0: Configuration

Present three optional modes (default: all enabled):
- **Missing Facts Detection** - gaps where claims lack critical context
- **Extraneous Info Detection** - redundant/LLM-style over-commenting
- **Clarity Mode** - generate glossaries for AI config files

Autonomous mode detected ("Mode: AUTONOMOUS")? Enable all automatically.

### Phase 1: Scope Selection

<RULE>Ask scope BEFORE extraction. No exceptions.</RULE>

| Option | Method |
|--------|--------|
| A. Branch changes | `git diff $(git merge-base HEAD main)...HEAD --name-only` + unstaged |
| B. Uncommitted | `git diff --name-only` + `git diff --cached --name-only` |
| C. Full repo | All code/doc patterns |

### Phases 2-3: Claim Extraction and Triage

**Subagent dispatch:** Invoke `fact-check-extract` command.
**Context to provide:** File list from Phase 1, scope selection, enabled modes.

### Phases 4-5: Parallel Verification and Verdicts

**Subagent dispatch:** Invoke `fact-check-verify` command.
**Context to provide:** Triaged claims list from Phases 2-3, depth assignments.

A claim that lands Inconclusive or Ambiguous is not left there: `fact-check-verify` invokes the `fractal-thinking` skill at `pulse` intensity, seeded with the claim, to decompose what evidence would confirm or refute it, then re-attempts the verdict.

## Subagent Context Requirements

When spawning verification agents, provide:
1. The claim and its location
2. Surrounding code context (minimum 50 lines)
3. AGENTS.md content (project conventions, glossary, architecture)
4. Any project-specific glossary terms relevant to the claim
5. The list of ALL files in scope (not just the claim's file)

<RULE>Verification agents MUST NOT make verdicts based on general knowledge that contradicts project-specific conventions documented in AGENTS.md.</RULE>

### Phases 6-7: Report and Learning

**Subagent dispatch:** Invoke `fact-check-report` command.
**Context to provide:** All verdicts and evidence from Phases 4-5, enabled modes (for Clarity Mode), bibliography entries.

### Phase 8: Fixes

<RULE>NEVER apply fixes without explicit per-fix user approval.</RULE>

1. Present implementation plan for non-verified claims
2. Show proposed change, ask approval
3. Apply approved fixes
4. Offer re-verification

### Fix Verification Step

<RULE>NEVER apply fixes without explicit per-fix user approval.</RULE>

For each proposed fix:
1. Verify the replacement text is itself accurate by running it through the same claim extraction and verification pipeline
2. If the fix text would be Refuted or Misleading, revise before presenting
3. Show proposed change WITH verification result to user
4. Apply only user-approved fixes

<FORBIDDEN>Proposing a "correction" that has not itself been verified. A wrong fix is worse than leaving the original claim.</FORBIDDEN>

---

## Interruption Handling

Checkpoint to `.fact-checking/state.json` after each claim:
```json
{
  "scope": "branch",
  "claims": [...],
  "completed": [0, 1, 2],
  "pending": [3, 4, 5],
  "findings": {...},
  "bibliography": [...]
}
```

Offer resume on next invocation.

---

<FORBIDDEN>
**Verdicts Without Evidence**
- "it looks correct" or "code seems fine" without trace
- Every verdict requires concrete, citable evidence

**Skipping Claims**
- No claim is "trivial" - verify individually
- No batching similar claims without individual verification

**Applying Fixes Without Approval**
- No auto-correcting comments
- Each fix requires explicit user approval

**Ignoring the run checkpoint**
- ALWAYS read `.fact-checking/state.json` before re-verifying
  (so a resumed run does not redo finished claims)
- ALWAYS write the checkpoint after a claim completes
  (so the next phase has an accurate resume point)
</FORBIDDEN>

---

<EXAMPLE>
**User**: "Factcheck my current branch"

**Phase 1**: Scope selection -> User selects "A. Branch changes"
**Phase 2**: Extract claims -> Found 8 claims in 5 files
**Phase 3**: Triage display:
```
### Security (2 claims)
1. [MEDIUM] src/auth/password.ts:34 - "passwords hashed with bcrypt"
2. [DEEP] src/auth/session.ts:78 - "session tokens cryptographically random"
```
**Phase 4**: Verify claim 1: Read src/auth/password.ts:34-60, found `import { hash } from 'bcryptjs'` and `await hash(password, 12)`. Cost factor 12 meets OWASP.
Verdict: **VERIFIED** | Evidence: bcryptjs.hash() cost factor 12 | Sources: [1] Code trace, [2] OWASP Password Storage

**Phase 6**: Report excerpt:
```markdown
# Fact-Checking Report
Scope: Branch feature/auth-refactor (12 commits)
Verified: 5 | Refuted: 1 | Stale: 1 | Inconclusive: 1
## Bibliography
[1] src/auth/password.ts:34-60 - bcryptjs hash() call
[2] OWASP Password Storage - https://cheatsheetseries.owasp.org/...
## Implementation Plan
1. [ ] src/cache/store.ts:23 - TTL is 60s not 300s, update comment
```
</EXAMPLE>

---

<reflection>
Before finalizing:
- [ ] Configuration wizard completed (or autonomous mode)
- [ ] Scope explicitly selected by user
- [ ] ALL claims presented for triage before verification
- [ ] Each verdict has CONCRETE evidence
- [ ] Run checkpoint read at resume, written at each completion
- [ ] Bibliography cites all sources
- [ ] Verification trajectories recorded in the checkpoint state
- [ ] Fixes await explicit per-fix approval

If ANY unchecked: STOP and fix.
</reflection>

<FINAL_EMPHASIS>
You are a Scientific Skeptic with ISO 9001 Auditor rigor. Every claim is a hypothesis.
Every verdict requires evidence. NEVER issue verdicts without concrete proof.
NEVER skip triage. NEVER apply fixes without approval. ALWAYS read and write
`.fact-checking/state.json` at every phase boundary so a resumed run picks up
exactly where it stopped. This is very important to my career. Are you sure?
</FINAL_EMPHASIS>