Borrowing it
Nothing to install: this file belongs to cbetz/ratebook. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/cbetz/ratebook/main/CLAUDE.mdgit clone --depth 1 https://github.com/cbetz/ratebookWrote 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/instructions/cbetz/ratebook/claude-md)<a href="https://agentmods.dev/instructions/cbetz/ratebook/claude-md"><img src="https://agentmods.dev/badge/instructions/cbetz/ratebook/claude-md.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 5.1 | $0.00897 | $0.00897 |
| Opus 5 | $0.00449 | $0.00449 |
| Sonnet 5 | $0.00179 | $0.00179 |
| Haiku 4.5 | $0.00090 | $0.00090 |
Grade A, and why
ratebook CLAUDE.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 7d 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 — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Ratebook — contributor & agent guide
The open rate engine for the electrified home: an openly licensed database of US electricity tariffs (parsed from utility PDFs by eval-harnessed LLM pipelines), a deterministic rate-calculation engine, and an MCP server — so any app, device, or agent can answer "what will this kWh cost me, and when should I charge?"
Status: pre-release. See docs/ROADMAP.md for what's shipped and what's next.
Repository layout (uv + pnpm monorepo)
packages/ratebook— the rate engine. Pure, deterministic functions over aTariffdata model (estimate_bill,estimate_annual,cheapest_charge_window,supported). No I/O.packages/ratebook-data— the data plant: URDB loader, the LLM extraction pipeline (extract.py), and the golden-set scorecard (golden.py).packages/ratebook-mcp— the MCP server exposinglookup_tariff,estimate_bill,compare_plans,best_charge_windowover the corpus + engine.packages/ratebook-ts— the TypeScript engine port (@ratebook/engine), kept in lockstep with the Python engine via shared JSON test vectors.packages/ratebook-homeassistant— a Home Assistant custom integration (electricity-price + cheapest-charge-window sensors) over the engine.
Development
uv sync # install all workspace packages + dev tools
uv run pytest # Python tests
uv run ruff check . # lint
uv run ratebook-data urdb # download URDB bulk CSV → data/raw/, load into data/ratebook.duckdb
uv run ratebook-mcp # run the MCP server (stdio)
pnpm -C packages/ratebook-ts install && pnpm -C packages/ratebook-ts test # TS engine + vectors
LLM extraction (ratebook-data's extract extra) additionally needs the anthropic SDK and an
API key; the engine, MCP, and HA paths never require it.
Conventions
- Python 3.12+, uv workspace, pytest (+ hypothesis for the engine's property tests), ruff. TypeScript: pnpm, vitest.
- The rate engine is pure functions, deterministic, boring, and bulletproof. Correctness
bugs here are customer-facing "your app lied about my bill" failures — every change is
property-tested and the engine is cross-validated against NREL's PySAM
utilityrate5. - The two engines must never diverge. Both reproduce
packages/ratebook/tests/vectors/v0_bills.jsonbyte-for-byte; regenerate withuv run python packages/ratebook/tests/generate_vectors.py. - Honesty about uncertainty is the brand. Every record should carry its source PDF URL, effective date, extraction confidence, and last-verified date. Never claim coverage or accuracy that hasn't been eval'd; "unknown" is a first-class answer. The accuracy scorecard is published content, not a marketing surface.
- Keep
docs/ROADMAP.mdcurrent at the end of each working session: what shipped, what's next, open questions.
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.
- 7d ago First seen · 68 lines · 897 tokens per session scan A 05b1d4a2fcd0
ratebook CLAUDE.md is an instructions file published in the GitHub repository cbetz/ratebook (1 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 897 tokens to every session, about $0.0045 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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