Fact Check
elvisun/newsjack
Extract factual claims from PR copy, verify each claim independently, attach concrete citations, and warn when certainty is low.
Attaches a numbered, URL-backed citation to every outside fact in an answer or document, rejecting quotes that aren't real.
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install NousResearch/hermes-agent grounded-citations --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/research/grounded-citations .claude/skills/grounded-citations && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .claude/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citationsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install NousResearch/hermes-agent grounded-citations --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/research/grounded-citations .agents/skills/grounded-citations && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .agents/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install NousResearch/hermes-agent grounded-citations --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/research/grounded-citations .cursor/skills/grounded-citations && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .cursor/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/NousResearch/hermes-agent.git --path skills/research/grounded-citations--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install NousResearch/hermes-agent grounded-citations --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/research/grounded-citations .gemini/skills/grounded-citations && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .gemini/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install NousResearch/hermes-agent grounded-citationsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/research/grounded-citations .github/skills/grounded-citations && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .github/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add NousResearch/hermes-agent --skill grounded-citations -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install NousResearch/hermes-agent grounded-citations --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/NousResearch/hermes-agent.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/research/grounded-citations .opencode/skills/grounded-citations && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "grounded-citations" agent skill from https://github.com/NousResearch/hermes-agent/tree/main/skills/research/grounded-citations into .opencode/skills/grounded-citations/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "grounded-citations", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
grounded-citationsAttaches a numbered, URL-backed citation to every outside fact in an answer or document, rejecting quotes that aren't real.
A ledger script, not the model's memory, owns every citation number here: each URL added gets a stable, idempotent id, so the same page always returns the same number across many search and extract rounds. The skill covers chat answers and written deliverables such as markdown, PDF, Word documents, and slides, and feeds a separate arxiv skill for conference-paper BibTeX work rather than replacing it.
For higher-stakes writing the same ledger doubles as a fact-checking chain: a cited claim needs a verbatim quote that actually appears on the fetched page, a claim drawn from the model's own knowledge gets flagged as unverified, and a verification step fails any draft whose cited sources carry no supporting evidence.
Read from SKILL.md and the folder at commit 14ec243. It shows what the files ask for, not the result of running them.
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Ships 2 files in scripts/ (Python), which the agent can run.
Shell commands in SKILL.md call:
pythonghFrom the folder's file list and the shell code blocks in SKILL.md.
No URLs in SKILL.md. Its commands use gh, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Grounded Citations loads about 3.1k tokens when it runs, and up to ~4.5k if it reads all its reference files. Until then it costs about 19 tokens; SKILL.md has 1,619 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
The full file from NousResearch/hermes-agent at commit 14ec243, republished under its MIT licence (© NousResearch). 1,619 words, ~3,147 tokens.
.claude/skills/grounded-citations/SKILL.md (or your agent's skills folder). This skill also uses 4 other files; get the full folder from GitHub.Every claim taken from an outside source gets an inline numbered citation and a
Sources: list, Perplexity-style. A ledger script owns the url → [n] mapping
so the numbers and URLs come from retrieval, never from memory — the model only
ever emits small integers it was handed.
For high-stakes work the same ledger doubles as a fact-checking chain: verbatim
quotes are attached to each source (rejected unless they literally appear in
the fetched page text), claims from model knowledge are flagged [unverified],
and verify --evidence fails any draft whose cited sources carry no evidence.
This skill covers answers in chat, written documents (markdown, PDF, docx,
slides), and research reports. It does not cover academic BibTeX pipelines —
for conference papers use the arxiv skill, which this skill
feeds (see references/citation-formats.md).
Use whenever an answer or artifact rests on information you fetched rather than knew:
Skip inline citations when the retrieval is incidental to another task — a quick syntax/version lookup mid-coding, casual conversation, creative writing. Mention a URL only if the user would plausibly want the link.
None beyond the standard toolset. scripts/sources.py is stdlib-only Python 3.
Retrieval comes from whatever is configured: web_search, web_extract,
browser_navigate, or terminal (curl, CLIs).
Ledger location: $HERMES_HOME/cache/citations/ledger.json (profile-aware).
Override per task with --ledger <path> or HERMES_CITATION_LEDGER.
S=~/.hermes/skills/research/grounded-citations/scripts/sources.py
python "$S" reset # start a clean ledger
python "$S" add https://example.com/a --title "A" # prints: [1]
python "$S" add https://example.com/b --title "B" # prints: [2]
python "$S" list # ledger table
python "$S" render # Sources: block
python "$S" verify draft.md # catch bad citationsadd is idempotent and URL-normalized: the same page always returns the same
id within a ledger, so ids stay stable across many search/extract rounds.
| Action | Command |
|---|---|
| Fresh ledger for a new task | sources.py reset |
| Register a source, get its id | sources.py add <url> [--title T] |
| Register several at once | sources.py add <url1> <url2> ... |
| Register from JSON tool output | sources.py ingest results.json |
| Attach verbatim evidence to a source | sources.py quote <id> --text "exact wording" --from page.txt |
| Show ledger | sources.py list [--json] |
| Render the Sources block | sources.py render [--style markdown|plain|footnotes|bibtex|evidence] [--only 1,3] |
| Render only what a draft cites | sources.py render --cited-in draft.md |
| Rewrite a draft's Sources block in place | sources.py render --replace-in draft.md |
| Check a draft's citations | sources.py verify draft.md [--strict] [--min-coverage 0.6] [--evidence] |
① Reset the ledger at the start of a task that will produce a grounded answer or document. Skip the reset when continuing work whose ids are already in a draft — reusing the ledger keeps the numbering stable.
② Register every source at retrieval time. After each web_search /
web_extract / browser_navigate / fetch, pass the URLs to sources.py add
(or pipe the raw JSON through sources.py ingest). Do this before writing
prose. Registering later, from memory, is the failure mode this skill exists to
prevent.
③ Write cite-while-drafting. Place the bracketed id(s) immediately after each sentence the source supports:
Ice floats because it is less dense than liquid water.[1][2]④ Append the Sources block with sources.py render --cited-in <draft> so
the id → URL mapping is generated mechanically from the ledger, not retyped.
For non-markdown targets pick the matching --style and follow
references/citation-formats.md for placement (footnotes in docx, endnotes in
PDF/LaTeX, a Sources slide in decks, per-page source lists in wiki output).
⑤ Verify before delivering — sources.py verify <draft> exits non-zero on
unknown ids, on a Sources block that disagrees with the ledger, or (with
--min-coverage) on prose that is too thinly cited. Fix and re-run.
⑥ Chat answers follow the same steps with the draft in your reply: register
sources, cite inline, end with the rendered Sources: list. For a short answer
you may render the block from sources.py render --only <ids> instead of
writing to a file.
"What are people saying about X" / "research X across the web" is not one
web_search. Fan out across source types, collect in parallel, then synthesise
with every claim attributed to the platform it came from:
| Source type | Route | What it adds |
|---|---|---|
| Open web | web_search → web_extract | official docs, articles, announcements |
| Community discussion | reddit-reading (search, thread) | real user experience, complaints, workarounds |
| Blogs / releases / changelogs | rss-feeds (read, discover) | dated primary posts, version history |
| Video | youtube-content | walkthroughs, demos, talks |
| Code | terminal with gh search repos / gh search issues | implementations, open bugs |
| X/Twitter | xurl (needs API access) | announcements, developer chatter |
The reddit-reading and rss-feeds skills are optional. If absent, install with
hermes skills install official/social-media/reddit-reading or
hermes skills install official/research/rss-feeds before using them.
Register every URL from every route in the ledger as it arrives (step ②). Keep opinion and measurement apart: a Reddit thread is evidence that users report something, not that it is true; pair it with a primary source or label it as sentiment. Report per-platform coverage gaps ("Reddit search returned nothing newer than March") rather than silently narrowing to what worked.
For work where the reader must be able to check the chain — medical, legal, financial, safety, disputed claims, or when the user asks for fact-checking — upgrade from citations to evidence:
① Attach a verbatim quote per source. After extracting a page, save its text to a file and attach the sentence(s) that carry each claim:
python "$S" quote 1 --text "Ice is about 9% less dense than liquid water." --from page1.txtThe quote is rejected unless it appears verbatim in the evidence text
(insensitive to whitespace, case, and markdown markup — inline links like
_[ERAP1](https://…)_ in extracted text match the plain prose a reader sees),
so a paraphrase or misremembered figure cannot masquerade as evidence.
Copy-paste from the fetched text; never retype. Quote the sentence as the
reader sees it — the matcher sees through the extractor's markup for you, so
you don't have to reproduce link syntax or escaped asterisks in your quote.
② Flag model-knowledge claims with [unverified]. A load-bearing claim
you could not source gets an explicit marker instead of a citation:
The refactor likely predates the 2.0 release.[unverified]verify --min-coverage counts [unverified] sentences as covered — the goal
is declared provenance for every claim, not a citation on every sentence.
If a key claim can be checked, check it; [unverified] is for what genuinely
cannot be, and a fact-check deliverable dominated by [unverified] markers
should say so in its summary.
③ Cross-check disputed facts against a second independent source. When two sources disagree, cite both readings with their own ids and quotes, and say which you weight and why. One source is reporting; two independent sources are corroboration.
④ Verify with the evidence gate and render the evidence block:
python "$S" verify report.md --evidence --min-coverage 0.5
python "$S" render --style evidence --replace-in report.md--evidence fails the draft if any cited source has no attached quote. The
evidence render style prints each source's quotes beneath its URL, so the
deliverable shows claim → source → exact supporting text with nothing taken on
faith. Use --replace-in <draft> to rewrite an existing Sources block in place
(idempotent — safe to re-run after attaching more quotes); --cited-in prints
to stdout instead. Both emit the heading ## Sources (--style plain emits
Sources:).
What --min-coverage counts. Coverage is
sentences with declared provenance / prose sentences. A prose sentence is a
non-empty line fragment of 4+ words after the Sources block, headings (#),
table rows (|), and fenced code are dropped; blockquote markers are stripped.
Provenance is declared by either a [n] citation or an [unverified] marker,
so a sentence carrying both counts once. Run verify without a threshold first
and read the info: stats: line to see the counts before picking a number.
[4], [4] must stay that source. Run reset
only between tasks.render. A hand-typed URL
is an unverified claim.web_search
description supports only what it literally says. Cite the extracted page
when the claim needs the body — web_extract it first.--ledger (or HERMES_CITATION_LEDGER) if their
outputs get merged, otherwise their ids will collide.web_extract
first, save the text, then quote --from that file.quote --text. The verbatim check will reject it; the
fix is to find the actual sentence, not to reword until something matches.[unverified] as an escape hatch. It marks the rare claim that
genuinely cannot be sourced; if most sentences carry it, the task needed more
retrieval, not more markers.render --replace-in <draft>; slicing
the file yourself risks a stale or duplicated block that verify then flags.python "$S" verify report.md --strict --min-coverage 0.5Green means: every [n] in the draft exists in the ledger, the Sources block
lists exactly the cited ids with the ledger's URLs, and the cited share of
source-bearing sentences meets the threshold. Read the warnings even when the
exit code is 0 — uncited registered sources usually mean a claim lost its
attribution during editing.
© NousResearch, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
SKILL.md and 4 other files (scripts, references) in skills/research/grounded-citations of NousResearch/hermes-agent.
Open the folder on GitHubat commit 14ec243
Grounded Citations next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Grounded Citations this skillNousResearch/hermes-agent | 252k | — | ~3.1k | Automated safety check: Pass | MIT | |
| Fact Checkelvisun/newsjack | 1.5k | — | ~5.6k | Automated safety check: Pass | MIT | |
| Citation Verification GuideGalaxy-Dawn/claude-scholar | 5.7k | 2 repos | ~1.9k | Automated safety check: Pass | MIT | |
| Article Fact Checkerdigoal/blog | 8.6k | — | ~939 | Automated safety check: Pass | GPL-2.0 | |
| Citation VerificationLight0305/Light-skills | 640 | — | ~3.4k | Automated safety check: Pass | MIT | |
| Reference VerifierYuan1z0825/nature-skills | 47k | 2 repos | ~1.4k | Automated safety check: Pass | Apache-2.0 |
elvisun/newsjack
Extract factual claims from PR copy, verify each claim independently, attach concrete citations, and warn when certainty is low.
Galaxy-Dawn/claude-scholar
Reference guidance for checking every citation in academic writing against canonical sources such as DOI, arXiv, CrossRef and Semantic Scholar, to catch fake or wrong references.
digoal/blog
三层审查模型,逐段逐句验证文章真伪、证据链与逻辑结构。Use when the user asks to fact-check, verify, audit, or evaluate the credibility of an article, essay, report, opinion piece, social-media post, or any written claim —…
Light0305/Light-skills
Verifies that every reference in a manuscript is real, correctly identified and actually supports its claim, and produces a citation registry for typesetting.
Yuan1z0825/nature-skills
Cross-checks each academic reference against several sources field by field, flags conflicts such as year, DOI, author order and page errors, and outputs a structured report.
zhongkaifu/TensorSharp
A skill your agent uses for web searches and current information lookups, finding sources, fact-checking, researching questions, comparing sources, or summarising web pages.
NousResearch/hermes-agent
Produces a presenter-led video from a topic or script plus one authorized presenter image, with captions, lip-sync checks and acceptance reports.
NousResearch/hermes-agent
Creates, reads, edits and templates Word .docx files with python-docx scripts, including tracked changes, comments, tables of contents and health checks.
NousResearch/hermes-agent
PDF files: create, read, merge, fill, OCR, edit text. An agent skill from NousResearch/hermes-agent.
NousResearch/hermes-agent
Premium scroll-driven landing pages; scroll = timeline. An agent skill from NousResearch/hermes-agent.
NousResearch/hermes-agent
Create, read, edit Excel .xlsx workbooks and CSVs. An agent skill from NousResearch/hermes-agent.
NousResearch/hermes-agent
Create, read, edit .pptx decks with python-pptx. An agent skill from NousResearch/hermes-agent.
Categories
Attaches a numbered, URL-backed citation to every outside fact in an answer or document, rejecting quotes that aren't real. A ledger script, not the model's memory, owns every citation number here: each URL added gets a stable, idempotent id, so the same page always returns the same number across many search and extract rounds. The skill covers chat answers and written deliverables such as markdown, PDF, Word documents, and slides, and feeds a separate arxiv skill for conference-paper BibTeX work rather than replacing it.
Grounded Citations fits situations like: writing a research summary or comparison that cites outside sources; producing a report, brief, or deck that quotes or paraphrases fetched pages; checking that a draft's citations are backed by real evidence.
Run `npx skills add NousResearch/hermes-agent --skill grounded-citations -a claude-code`. Or copy the skill folder (skills/research/grounded-citations in NousResearch/hermes-agent) into .claude/skills/grounded-citations in your project. Claude Code loads it when a task matches its description.
Run `npx skills add NousResearch/hermes-agent --skill grounded-citations -a codex`. Or copy the skill folder (skills/research/grounded-citations in NousResearch/hermes-agent) into .agents/skills/grounded-citations in your project. Codex loads it when a task matches its description.
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add NousResearch/hermes-agent --skill grounded-citations -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/grounded-citations, .gemini/skills/grounded-citations, .github/skills/grounded-citations and .opencode/skills/grounded-citations in your project.
Going by SKILL.md and its folder, Grounded Citations needs Python for the scripts in its folder and the command-line tools its instructions call (python and gh). Our summary lists: Python 3 (stdlib only) to run the ledger script; A retrieval tool such as web search, web fetch, or a browser.
SKILL.md contains no URLs. Its commands use gh, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
Grounded Citations is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.
About 3.1k tokens (SKILL.md is roughly 13k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.4k tokens, read only when the agent opens those files.
Skills that share tags, products or a category with Grounded Citations: Fact Check (elvisun/newsjack, 1.5k stars), Citation Verification Guide (Galaxy-Dawn/claude-scholar, 5.7k stars), Article Fact Checker (digoal/blog, 8.6k stars) and Citation Verification (Light0305/Light-skills, 640 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
NousResearch (a GitHub organization) maintains it in NousResearch/hermes-agent, which has 252,110 GitHub stars. The repository holds 31 skills in this directory. The repository was last updated on October 9, 2026.
Source: NousResearch/hermes-agent on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.