Borrowing it
Nothing to install: this file belongs to svyatov/handrail. 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/svyatov/handrail/main/CLAUDE.mdgit clone --depth 1 https://github.com/svyatov/handrailWrote 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/svyatov/handrail/claude-md)<a href="https://agentmods.dev/instructions/svyatov/handrail/claude-md"><img src="https://agentmods.dev/badge/instructions/svyatov/handrail/claude-md/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/instructions/svyatov/handrail/claude-md"><img src="https://agentmods.dev/badge/instructions/svyatov/handrail/claude-md.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 | $0.00616 | $0.00616 |
| Opus 5.5 | $0.00246 | $0.00246 |
| Sonnet 5.5 | $0.00123 | $0.00123 |
| Haiku 4.5 | $0.00062 | $0.00062 |
Grade A, and why
handrail 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 27d 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 — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.
handrail
docs/spec.md is the behavioural source of truth, about 100 KB, one bullet per line and
up to 4 KB each, so a 30-line range runs 15-40 KB. Each bullet or table row opens with
its field or bold term: find it with grep -n '^[-|] [`*]*<term>' docs/spec.md and
read those lines alone. GLOSSARY.md defines the vocabulary.
Commands
mise run test # go test -race -shuffle=on ./...
mise run cover # the same run with coverage, fails under 95%
mise run lint # go mod tidy -diff and verify, go fix -diff, golangci-lint run and fmt --diff, then scripts/check-{doc-paths,flag-sources,dashes}.sh
mise run vuln # govulncheck through go run, so it stays out of go.mod
mise run fuzz # 30s (FUZZTIME) per parser fuzz target; a crash input lands in testdata/fuzz/, commit it
mise run build # the release build
mise run release-check # goreleaser check, the version pin, and the CHANGELOG section the release body is cut from
CI calls these same tasks, so a local pass means what a green check means.
Two constraints the build enforces
- One third-party runtime dependency,
mvdan.cc/sh/v3(ADR 0011).depguardallows only the stdlib, this module andmvdan.cc/sh/v3/syntaxoutside_test.go, and deniesos/exec;github.com/rogpeppe/go-internalis the sole test-only one. os.Exitonly inmain.go, sorun()returns an exit code and stays testable.forbidigoenforces it.
Tests
testscript over the compiled binary is the primary seam: a new case goes in
testdata/script/*.txtar, not a new _test.go. Unit tests under internal/ are only
for what a process boundary cannot produce. See docs/adr/0009-testing-strategy.md.
Agent skills
Issue tracker
Issues live as GitHub issues in svyatov/handrail, managed via the gh CLI. See docs/agents/issue-tracker.md.
Triage labels
The seven canonical roles (two category, five state), each label string equal to its name. See docs/agents/triage-labels.md.
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.
- 27d ago Changed · +1 lines · +32 tokens per session 4efdb520131d
- 28d ago Changed · +5 tokens per session 2c9662ad533f
- 29d ago Changed · +3 lines · +116 tokens per session a86adcd83463
- 1mo ago Changed · +3 lines · +73 tokens per session c7f1b50d8baf
- 1mo ago First seen · 46 lines · 390 tokens per session scan A 4263bdac069f
handrail CLAUDE.md is an instructions file published in the GitHub repository svyatov/handrail (2 stars, last pushed 6d ago), licensed MIT. It adds 616 tokens to every session, about $0.0025 per session on Opus 5.5. 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.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.