mcp-server-builder

name	mcp-server-builder
description	You need to expose an internal/external REST API to an LLM agent
executor	HYBRID
skill_id	engineering.cs-engineering.mcp-server-builder
status	ADOPTED
security	{"level":"standard","pii":false,"approval_required":false}
anchors	["engineering","design"]
tier	2
input_schema	[{"name":"code_or_task","type":"string","description":"Code snippet, script, or task description to process","required":true}]
output_schema	[{"name":"plan","type":"string","description":"Strategic plan or design document"},{"name":"next_steps","type":"array","description":"List of recommended next steps"}]

MCP Server Builder

Tier: POWERFUL
Category: Engineering
Domain: AI / API Integration

Overview

Use this skill to design and ship production-ready MCP servers from API contracts instead of hand-written one-off tool wrappers. It focuses on fast scaffolding, schema quality, validation, and safe evolution.

The workflow supports both Python and TypeScript MCP implementations and treats OpenAPI as the source of truth.

Core Capabilities

• Convert OpenAPI paths/operations into MCP tool definitions
• Generate starter server scaffolds (Python or TypeScript)
• Enforce naming, descriptions, and schema consistency
• Validate MCP tool manifests for common production failures
• Apply versioning and backward-compatibility checks
• Separate transport/runtime decisions from tool contract design

When to Use

• You need to expose an internal/external REST API to an LLM agent
• You are replacing brittle browser automation with typed tools
• You want one MCP server shared across teams and assistants
• You need repeatable quality checks before publishing MCP tools
• You want to bootstrap an MCP server from existing OpenAPI specs

Key Workflows

1. OpenAPI to MCP Scaffold

1. Start from a valid OpenAPI spec.
2. Generate tool manifest + starter server code.
3. Review naming and auth strategy.
4. Add endpoint-specific runtime logic.

python3 scripts/openapi_to_mcp.py \
  --input openapi.json \
  --server-name billing-mcp \
  --language python \
  --output-dir ./out \
  --format text

Supports stdin as well:

cat openapi.json | python3 scripts/openapi_to_mcp.py --server-name billing-mcp --language typescript

2. Validate MCP Tool Definitions

Run validator before integration tests:

python3 scripts/mcp_validator.py --input out/tool_manifest.json --strict --format text

Checks include duplicate names, invalid schema shape, missing descriptions, empty required fields, and naming hygiene.

3. Runtime Selection

• Choose Python for fast iteration and data-heavy backends.
• Choose TypeScript for unified JS stacks and tighter frontend/backend contract reuse.
• Keep tool contracts stable even if transport/runtime changes.