langchain-tool-builder SKILL.md skillA
langchain-tool-builder from simbajigege/book2skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add simbajigege/book2skills/langchain-tool-builder@git:20260603.b786d64Pins git:20260603.b786d64 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- simbajigege/book2skills
- Path
skills/langchain-tool-builder/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260603.b786d64, committed Jun 3, 2026
- Size
- 10,025 bytes
- Repository stars
- 202
- License
- MIT
Build LangChain (Python) tools using Claude Code's fail-closed design pattern — unified name/schema/security/execution in one class, with automatic three-layer execution (validate → permission → call). Use this skill whenever the user wants to define a new LangChain tool, add permission or validation logic to an existing tool, set up the ClaudeStyleTool base class in a project, or asks about "build_tool", "Claude Code style tool", "工具定义", or "langchain tool with permissions". Also trigger when…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# LangChain Tool Builder Helps define LangChain (Python) tools using Claude Code's `buildTool()` pattern: a unified class that co-locates identity, schema, security properties, and execution logic, with fail-closed defaults so new tools are safe by default. ## Why this pattern matters Claude Code enforces three things that vanilla LangChain tools lack: 1. **Fail-closed defaults** — `is_read_only`, `is_destructive`, `is_concurrency_safe` all default to False. A tool that forgets to declare its properties is conservatively treated as write-capable. 2. **Layered execution** — `validate_semantics → check_permissions → _call` are separate methods, so validation logic doesn't bleed into permission logic or business logic. 3. **Self-contained definition** — schema, description, security metadata, and execution all live in one class. No separate permission middleware to wire up. ## Workflow ### Step 1 — Install the base class Check if `claude_style_tool.py` exists in the project's utils directory. The expected location for the `ai-base` project is: `/Users/jigege/ai-base/backend/base/utils/claude_style_tool.py` …
Read the whole file at its exact version.
How to install
mdr add simbajigege/book2skills/langchain-tool-builder@sha256:ffcec65eddfad28dThe line at the top of this page pins the label git:20260603.b786d64, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_5bcrrgexdpvddcyj)
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Versions
The registry has recorded 1 version of this file, committed on Jun 3, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (10025 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
simbajigege/book2skills · 202 stars · license MIT · pushed 2026-08-26 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_5bcrrgexdpvddcyj GET https://markdownregistry.com/api/v1/resolve?ref=simbajigege/book2skills/langchain-tool-builder GET https://markdownregistry.com/api/v1/blob/ffcec65eddfad28da13446cfdd7e607a2700be1391130fd9e57b834db60e14f1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.