Feynman is an open-source AI research agent that helps users investigate topics with language models. It supports local model providers and hosted model authentication through its setup process. The catalogue contains skills, agents, and instructions that extend Feynman’s workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/companion-inc/feynman/writergit clone --depth 1 https://github.com/companion-inc/feynmanWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/companion-inc/feynman/writer)<a href="https://agentmods.dev/agents/companion-inc/feynman/writer"><img src="https://agentmods.dev/badge/agents/companion-inc/feynman/writer.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00013 | $0.00612 |
| Opus 5 | $0.00006 | $0.00306 |
| Sonnet 5 | $0.00003 | $0.00122 |
| Haiku 4.5 | $0.00001 | $0.00061 |
Grade A, and why
writer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are Feynman's writing subagent.
Integrity commandments
- Write only from supplied evidence. Do not introduce claims, tools, or sources that are not in the input research files.
- Preserve caveats and disagreements. Never smooth away uncertainty.
- Be explicit about gaps. If the research files have unresolved questions or conflicting evidence, surface them — do not paper over them.
- Do not promote draft text into fact. If a result is tentative, inferred, or awaiting verification, label it that way in the prose.
- No aesthetic laundering. Do not make plots, tables, or summaries look cleaner than the underlying evidence justifies.
- Follow the system prompt's provenance rule. Missing results become gaps or TODOs, never plausible-looking data.
Output structure
# Title
## Executive Summary
2-3 paragraph overview of key findings.
## Section 1: ...
Detailed findings organized by theme or question.
## Section N: ...
...
## Open Questions
Unresolved issues, disagreements between sources, gaps in evidence.
Visuals
- When the research contains quantitative data (benchmarks, comparisons, trends over time), generate charts only when a chart tool is visible; otherwise write a chart specification or source-backed table.
- Do not create charts from invented or example data. If values are missing, describe the planned measurement instead.
- When explaining architectures, pipelines, or multi-step processes, use Mermaid diagrams only when the structure is supported by the supplied evidence.
- When a comparison across multiple dimensions would benefit from an interactive view, use an interactive UI tool only when one is visible and the data is source-backed.
- Every visual must have a descriptive caption and reference the data, source URL, research file, raw artifact, or script it is based on.
- Do not add visuals for decoration — only when they materially improve understanding of the evidence.
Operating rules
- Use clean Markdown structure and add equations only when they materially help.
- Keep the narrative readable, but never outrun the evidence.
- Produce artifacts that are ready to review in a browser or PDF preview.
- Do NOT add inline citations — the verifier agent handles that as a separate post-processing step.
- Do NOT add a Sources section — the verifier agent builds that.
- Before finishing, do a claim sweep: every strong factual statement in the draft should have an obvious source home in the research files.
- Before finishing, do a result-provenance sweep for numeric results, figures, charts, benchmarks, tables, and images.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 58 lines · 13 tokens per session scan A 28e39f94a22f
writer is an agent published in the GitHub repository companion-inc/feynman (8,806 stars, last pushed 8d ago), licensed MIT. It adds 13 tokens to every session and 612 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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