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 instructions/7vignesh/fossel/agents-mdgit clone --depth 1 https://github.com/7vignesh/fosselWhat 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 | $0.01412 | $0.01412 |
| Opus 5 | $0.00706 | $0.00706 |
| Sonnet 5 | $0.00282 | $0.00282 |
| Haiku 4.5 | $0.00141 | $0.00141 |
Grade A, and why
fossel AGENTS.md 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 2d 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 — 102 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AGENTS.md
Orientation and roadmap for agents working on Fossel.
What Fossel is
A local-first MCP memory server for coding assistants. It stores per-repo conventions, bug fixes, decisions and reviewer patterns in SQLite with FTS5 search, and serves them back to Cursor / Claude Desktop / any stdio MCP client. The guiding constraint behind almost every decision: no LLM, no model download, no network at runtime. Where a general memory tool would call an LLM, Fossel either uses a heuristic or hands the judgment back to the client's own model.
Layout
src/db/—client.ts(singleton connection, WAL),migrate.ts(the runtime source of truth: sequential named migrations),schema.sql(hand-maintained reference of the final shape).src/lib/— domain logic:repo.ts(canonical repo-key resolution + alias merging),context.ts(retrieval assembly),fts.ts(three-tier FTS),fusion.ts(weighted RRF),embeddings.ts,idf.ts,vector-index.ts,merge.ts(dedupe),dedupe.ts,inference.ts,temporal.ts.src/tools/— thin MCP tool registrations. Each resolves the repo, calls a lib function, and returns{ content: [{ type: "text" }] }, catching errors intoisError: truerather than throwing. Keep tools thin; put logic inlib.bench/— retrieval benchmark.npm run benchscores fts/vector/hybrid on a committed eval set;npm run bench:checkfails on drift;npx tsx bench/sweep.tstunes constants.
Working agreement
- Measure retrieval changes. Anything touching search must be run through
npm run benchand the results snapshot committed. Keep a change only if the numbers support it; several ideas have been implemented, measured, and removed (see the "tried and rejected" notes infusion.tsandfts.ts). Do not re-try those blindly. - Verify before claiming done.
npm run ci(typecheck + typecheck:bench + tests + build + smoke) must pass. Commits should be independently green. - Windows dev shell is PowerShell 5 — use
;not&&; multi-line commit messages go through a file (git commit -F), not inline-m. - The fusion weight is coupled to embedder quality. Re-sweep
DEFAULT_VECTOR_WEIGHTwhenever the embedder changes. - Stored embedding vectors must stay a pure function of their own text, or every vector goes stale on any corpus change (forcing a full re-index). Corpus-derived weighting (IDF) is applied to the query side only for this reason.
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.
- 2d ago First seen · 102 lines · 1,412 tokens per session scan A da204e666ac1
fossel AGENTS.md is an instructions file published in the GitHub repository 7vignesh/fossel (4 stars, last pushed 5d ago), licensed MIT. It adds 1,412 tokens to every session, about $0.0071 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 2026-08-31.
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