agent-tool-builder SKILL.md skillA
agent-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/agent-tool-builder@git:20260612.4cde403Pins git:20260612.4cde403 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- simbajigege/book2skills
- Path
skills/agent-tool-builder/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260612.4cde403, committed Jun 12, 2026
- First version recorded
- Jun 12, 2026
- Size
- 8,531 bytes
- Repository stars
- 190
- License
- MIT
Define agent tools using the fail-closed design pattern — unified name/schema/security/execution in one class, with three-layer execution (validate → permission → call). Use this skill whenever the user wants to define a new agent tool, add permission or validation logic to an existing tool, or asks about 'build a tool', '定义一个工具', 'create a tool for X', '工具定义'. Framework-agnostic: works with hermes-agent, LangChain, or any Python agent framework.
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
# Agent Tool Builder Helps define agent tools using the fail-closed design 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 Three things that ad-hoc tool definitions 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 place. No separate middleware to wire up. --- ## Workflow ### Step 1 — Identify the target framework Ask which agent framework the tool will be registered in (e.g. hermes-agent, LangChain, plain Python). This determines the import path and registration method, but the design principles are identical. Check if `agent_tool_base.py` exists in the project's utils/tools directory. …
Read the whole file at its exact version.
How to install
mdr add simbajigege/book2skills/agent-tool-builder@sha256:65e39fc47093b637The line at the top of this page pins the label git:20260612.4cde403, 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_t6b5q6e6d264plbj)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, all committed on Jun 12, 2026.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260612.4cde403 latest | 2026-06-12 | 4cde403 | 8,531 B | A | view · diff |
| git:20260612.cf2f218 | 2026-06-12 | cf2f218 | 8,529 B | A | view |
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 (8531 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 · 190 stars · license MIT · pushed 2026-08-26 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_t6b5q6e6d264plbj GET https://markdownregistry.com/api/v1/resolve?ref=simbajigege/book2skills/agent-tool-builder GET https://markdownregistry.com/api/v1/blob/65e39fc47093b6376bf21b2e50191dc477995bceb00c49f38583af7f9b3df1c2
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.
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