build-custom-mcp-server SKILL.md skillA
build-custom-mcp-server from pjt222/agent-almanac is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add pjt222/agent-almanac/build-custom-mcp-server@v1.0Pins v1.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- pjt222/agent-almanac
- Path
i18n/caveman-lite/skills/build-custom-mcp-server/SKILL.md- Versions recorded
- 4
- Latest version
- v1.0, committed Aug 17, 2026
- First version recorded
- Apr 19, 2026
- Size
- 9,939 bytes
- Repository stars
- 43
- License
- MIT
Build a custom MCP (Model Context Protocol) server that exposes domain-specific tools to AI assistants. Covers server implementation in Node.js or R, tool definitions, transport configuration, and testing with Claude Code. Use when you need to expose custom functionality beyond what mcptools provides, when building specialized domain-specific AI integrations, or when wrapping existing APIs or services as MCP tools.
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
# Build Custom MCP Server
Create a custom MCP server that exposes domain-specific tools to AI assistants.
## When to Use
- Need to expose custom functionality to Claude Code or Claude Desktop
- Building specialized tools beyond what mcptools provides
- Creating a domain-specific AI assistant integration
- Wrapping existing APIs or services as MCP tools
## Inputs
- **Required**: List of tools to expose (name, description, parameters, behavior)
- **Required**: Implementation language (Node.js or R)
- **Required**: Transport type (stdio or HTTP)
- **Optional**: Authentication requirements
- **Optional**: Docker packaging needs
## Procedure
### Step 1: Define Tool Specifications
Before writing code, define each tool:
```yaml
tools:
- name: query_database
description: Execute a read-only SQL query against the analysis database
parameters:
query:
type: string
description: SQL SELECT query to execute
required: true
limit:
type: integer
description: Maximum rows to return
default: 100
returns: JSON array of result rows
- name: run_analysis
…Read the whole file at its exact version.
How to install
mdr add pjt222/agent-almanac/build-custom-mcp-server@sha256:11919f3d82ee501cThe line at the top of this page pins the label v1.0, 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_cwhsywlqbmpv7un3)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 4 versions of this file, between Apr 19, 2026 and Aug 17, 2026, about one every 40 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1.0 latest | 2026-08-17 | a784899 | 9,939 B | A | view · diff |
| v1.0 | 2026-06-05 | 33b561c | 9,910 B | A | view · diff |
| v1.0 | 2026-04-19 | 239796d | 9,906 B | A | view · diff |
| v1.0 | 2026-04-19 | e334ebd | 9,969 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 (9939 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
pjt222/agent-almanac · 43 stars · license MIT · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_cwhsywlqbmpv7un3 GET https://markdownregistry.com/api/v1/resolve?ref=pjt222/agent-almanac/build-custom-mcp-server GET https://markdownregistry.com/api/v1/blob/11919f3d82ee501c06d9637eb9bf6121fb9c2d62791fca63c1cbdb4287d097ca
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.