Borrowing it
Nothing to install: this file belongs to tacoda/keystone. 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/tacoda/keystone/main/.claude/agents/keystone-review-functional.mdgit clone --depth 1 https://github.com/tacoda/keystoneWrote 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/tacoda/keystone/keystone-review-functional)<a href="https://agentmods.dev/agents/tacoda/keystone/keystone-review-functional"><img src="https://agentmods.dev/badge/agents/tacoda/keystone/keystone-review-functional/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/tacoda/keystone/keystone-review-functional"><img src="https://agentmods.dev/badge/agents/tacoda/keystone/keystone-review-functional.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00020 | $0.00195 |
| Opus 5.5 | $0.00008 | $0.00078 |
| Sonnet 5.5 | $0.00004 | $0.00039 |
| Haiku 4.5 | $0.00002 | $0.00019 |
Grade A, and why
keystone-review-functional 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 1mo 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.
This is a copy
94% identical to review-functional — 7 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Sensor: review-functional
An agent reads the diff and reports logic, correctness, and behavior issues.
- Trigger — review (review phase).
- Inputs — the diff, the spec, and any region-relevant context (idioms, state).
- Exit condition — the reviewer reports no blocking issues, or the user accepts the remaining notes.
- Output — findings list keyed by file and line, each tagged blocking / nit / note.
- State writes — none.
How the agent is invoked is adapter-specific — sub-agent, separate session, MCP tool, or a checklist prompt — see .charter/adapters/<your-agent>/sensors.md. The bootstrap action records whether this sensor is available for the project's active adapter.
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.
- 1mo ago First seen · 19 lines · 20 tokens per session scan A cfafcf5dbb42
keystone-review-functional is an agent published in the GitHub repository tacoda/keystone (44 stars, last pushed 3mo ago), licensed MIT. It adds 20 tokens to every session and 195 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 94% identical to review-functional, differing in 7 lines, and is treated as a copy.
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