What is craftor-mcp-engineer?

An engineering guide for building MCP servers. MCP, or Model Context Protocol, is a standard way for AI tools to access functions and data through a server.

Use it to build JSON-RPC 2.0 server processes, support local and network connections through stdio, SSE, and WebSockets, route tool requests, and generate settings for supported AI clients.

It helps handle the network connections, request messages, responses, and client settings needed to connect AI applications to those servers.

How djsushilkumar/Craftor configures Claude Code and Codex

Reuse

Borrowing it

Nothing to install: this file belongs to djsushilkumar/Craftor. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/djsushilkumar/Craftor/main/.agents/skills/craftor-mcp-engineer/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/djsushilkumar/Craftor

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/djsushilkumar/craftor/craftor-mcp-engineer/github.svg)](https://agentmods.dev/skills/djsushilkumar/craftor/craftor-mcp-engineer)

Your own site

<a href="https://agentmods.dev/skills/djsushilkumar/craftor/craftor-mcp-engineer"><img src="https://agentmods.dev/badge/skills/djsushilkumar/craftor/craftor-mcp-engineer/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/djsushilkumar/craftor/craftor-mcp-engineer"><img src="https://agentmods.dev/badge/skills/djsushilkumar/craftor/craftor-mcp-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,449 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00054	$0.01449
Opus 5.5	$0.00022	$0.00580
Sonnet 5.5	$0.00011	$0.00290
Haiku 4.5	$0.00005	$0.00145

Measured 2mo ago against content hash a787921fb6ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

craftor-mcp-engineer 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 2mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate_jsonrpc.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.agents/skills/craftor-mcp-engineer/SKILL.md · 151 lines

How it starts

The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Craftor MCP Engineer Skill

1. Mission & Identity

You are the Lead MCP Engineer for Craftor. Your mission is to build, maintain, and optimize the Model Context Protocol (MCP) server daemon. You implement multi-transport runtimes (stdio for local CLIs/IDEs, SSE and WebSockets for cloud and multi-site execution), route tool requests, stream structured resources, format JSON-RPC 2.0 responses, and generate client configuration adapters for all 8 target AI clients.

2. Core Responsibilities

MCP Server Core Daemon: Build the modular MCP server runtime implementing official 2024+ specifications (tools/list, tools/call, resources/list, resources/read, prompts/list, prompts/get).
Multi-Transport Runtime: Implement zero-latency stdio stream handlers and high-concurrency Server-Sent Events (SSE) endpoints with HTTP/2 multiplexing.
Client Adapter Presets: Maintain automated configuration generators for Claude Desktop, Claude Code, Cursor, Codex, Antigravity, VS Code, Gemini, and OpenAI clients.
JSON-RPC 2.0 Serialization & Protocol Routing: Enforce strict framing, backpressure handling, request deduplication, and standardized error envelopes.
Session & State Management: Maintain active connection sessions, authentication handshakes, and transport auto-reconnection.

3. Required Expertise & Competency Matrix

Model Context Protocol (MCP): Specification primitives (Tools, Resources, Prompts, Transports, Capabilities negotiation).
Node.js / TypeScript & Systems Programming: Stream management (process.stdin/stdout), asynchronous event loops, HTTP/2, EventSource/SSE.
JSON-RPC 2.0: Standard protocol codes (-32700 Parse error, -32600 Invalid Request, -32601 Method not found, -32602 Invalid params, -32603 Internal error).
Multi-Client Ecosystem Configurations: claude_desktop_config.json, .cursor/mcp.json, VS Code settings.json, Antigravity plugin manifests.

4. Inputs & Contextual Triggers

Read the full file on GitHub · 151 lines

Files

What ships with it

10 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

2mo ago First seen · 151 lines · 54 tokens per session scan A a787921fb6ce

Subscribe to this mod's changes

craftor-mcp-engineer is a skill published in the GitHub repository djsushilkumar/Craftor (0 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 1,449 once invoked, about $0.0002 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.

Backend and APIs Building agents

craftor-mcp-engineer next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
craftor-mcp-engineerdjsushilkumar/Craftor	Skill	0	2mo ago	Apache-2.0	A	54	Claude Code, Codex
mem0-oss-to-platformmem0ai/mem0	Skill	68k	2d ago	Apache-2.0	A	217	Claude Code, Codex
azure-mgmt-botservice-dotnetmicrosoft/skills	Skill	3.2k	yesterday	MIT	A	78	Claude Code
fastapi-router-pymicrosoft/skills	Skill	3.2k	yesterday	MIT	A	46	Claude Code
dev-runtimelangwatch/langwatch	Skill	5.0k	yesterday	Apache-2.0	A	172	Claude Code
api-designericrisco/rsc-harness	Skill	503	2d ago	MIT	A	105	Claude Code, Codex
migrate-segw-to-raparc-mcp/arc-1	Skill	252	yesterday	MIT	A	106	Claude Code

Craftor: Skill for Claude Code