The Verifier is Feynman’s citation and source-checking subagent. It receives a draft from the Writer and the research files it was built from, then post-processes the draft to add inline citations, verify that every source URL is live and actually supports the attached claim, and build the final numbered Sources section. It is the last agent to run before delivery.Documentation Index
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Role
The Verifier does not rewrite prose. Its job is to anchor claims, check URLs, and clean dead links. It produces the cited brief — the same document structure as the input draft, but with citations inserted throughout and a verified Sources section appended.What the Verifier does
Anchor every factual claim
Insert inline citations directly after each claim using the format
[1], [2], etc. Multiple sources for one claim: [7, 12]. Hedged or opinion statements do not need citations.Verify every source URL
Use
fetch_content to confirm each URL resolves and contains the claimed content. Flag dead links. If an alternative URL (archived version, mirror, updated link) can be found, substitute it. If none is found, remove the source and all claims that depended solely on it.Remove unsourced claims
If a factual claim in the draft cannot be traced to any source in the research files, either find a source or remove the claim. Unsourced factual claims are not left in the output.
Citation rules
- Every factual claim gets at least one citation:
Transformers achieve 94.2% on MMLU [3]. - Multiple sources for one claim:
Recent work questions benchmark validity [7, 12]. - No orphan citations — every
[N]in the body must appear in Sources. - No orphan sources — every entry in Sources must be cited at least once.
- Hedged or opinion statements do not need citations.
- When multiple research files use different numbering, merge into a single unified sequence starting from
[1]. Deduplicate sources that appear in multiple files.
Source verification logic
| URL status | Action |
|---|---|
| Live | Keep as-is |
| Dead / 404 | Search for alternative (archive, mirror, updated link). If none found, remove source and all claims that depended solely on it. |
| Redirects to unrelated content | Treat as dead |
Integrity rules
- Verify meaning, not just topic overlap. A citation is valid only if the source actually supports the specific number, quote, or conclusion attached to it.
- Refuse fake certainty. Do not use
verified,confirmed, orreproducedunless the research files provide the underlying evidence. - Do not preserve claims that cannot be sourced. Remove or soften unsupported factual claims rather than leaving them in.
Output file
The Verifier saves its output to the path specified by the lead agent. In standard workflows this is:Manual invocation
You can run the Verifier directly on a specific draft:cited.md as a fallback).