Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add san-npm/skills-ws --skill mcp-server-buildergit clone --depth 1 https://github.com/san-npm/skills-wsWrote 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.
[](https://agentmods.dev/skills/san-npm/skills-ws/mcp-server-builder)<a href="https://agentmods.dev/skills/san-npm/skills-ws/mcp-server-builder"><img src="https://agentmods.dev/badge/skills/san-npm/skills-ws/mcp-server-builder/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.
<a href="https://agentmods.dev/skills/san-npm/skills-ws/mcp-server-builder"><img src="https://agentmods.dev/badge/skills/san-npm/skills-ws/mcp-server-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00095 | $0.01071 |
| Opus 5 | $0.00048 | $0.00535 |
| Sonnet 5 | $0.00019 | $0.00214 |
| Haiku 4.5 | $0.00010 | $0.00107 |
Grade A, and why
mcp-server-builder 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 10d ago.
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.
How it starts
The opening of the file, as written. The whole thing — 39 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MCP Server Builder — Production Skill
Pick the transport first. stdio for local-process servers (Claude Desktop, CLI). Streamable HTTP for everything remote/shared/monetized —
StreamableHTTPServerTransportin TS (@modelcontextprotocol/sdkv1.x),FastMCPin Python. The two standard transports are stdio and Streamable HTTP. The old HTTP+SSE transport (/sse+/messages) is legacy/deprecated (replaced in spec 2025-03-26, current spec 2025-11-25); ship it only as a backward-compat appendix for old clients (see §2c).
Build production-grade Model Context Protocol servers that wrap any REST API into AI-callable tools, with three-tier auth, monetization, and battle-tested deployment.
Related skills: for the consuming side (connecting to / calling MCP servers) see
mcp-client; for general agent architecture seeai-agent-building; for REST contract/versioning design seeapi-design; for the Stripe billing details behind §7 seestripe-billing; for the SSRF/secret-handling depth in §9 seesecurity-hardening.
Reference guide
Read only the references needed for the current request:
- When to Use: references/when-to-use.md
- 1. MCP Architecture Overview: references/1-mcp-architecture-overview.md
- 2. Server Setup — TypeScript (@modelcontextprotocol/sdk): references/2-server-setup-typescript-modelcontextprotocol-sdk.md
- 3. Server Setup — Python (FastMCP, the
mcppackage): references/3-server-setup-python-fastmcp-the-mcp-package.md - 4. Tool Schema Design (JSON Schema): references/4-tool-schema-design-json-schema.md
- 5. REST API to MCP Pattern: references/5-rest-api-to-mcp-pattern.md
- 6. Three-Tier Authentication: references/6-three-tier-authentication.md
- 7. Monetization Strategy: references/7-monetization-strategy.md
- 8. Express.js Architecture: references/8-express-js-architecture.md
- 9. Security: references/9-security.md
- 10. Monitoring & Logging: references/10-monitoring-logging.md
- 11. Deployment: references/11-deployment.md
- 12. Testing with Claude Desktop & Claude Code: references/12-testing-with-claude-desktop-claude-code.md
- 13. Listing on mcpservers.org: references/13-listing-on-mcpservers-org.md
- Tools: references/tools.md
- Quick Start: references/quick-start.md
- 14. Environment Variables Reference: references/14-environment-variables-reference.md
- 15. Common Patterns & Gotchas: references/15-common-patterns-gotchas.md
- 16. Complete Production Checklist: references/16-complete-production-checklist.md
- Appendix A: Graceful Shutdown: references/appendix-a-graceful-shutdown.md
- Appendix B: Redis Rate Limiter (Production): references/appendix-b-redis-rate-limiter-production.md
- Appendix C: Tool Registration Helper: references/appendix-c-tool-registration-helper.md
What ships with it
23 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.
- agents/openai.yaml 207 B
- references/1-mcp-architecture-overview.md 3.2 KB
- references/10-monitoring-logging.md 1.9 KB
- references/11-deployment.md 4.2 KB
- references/12-testing-with-claude-desktop-claude-code.md 4.9 KB
- references/13-listing-on-mcpservers-org.md 543 B
- references/14-environment-variables-reference.md 1.1 KB
- references/15-common-patterns-gotchas.md 2.7 KB
- references/16-complete-production-checklist.md 1.5 KB
- references/2-server-setup-typescript-modelcontextprotocol-sdk.md 15 KB
- references/3-server-setup-python-fastmcp-the-mcp-package.md 4.3 KB
- references/4-tool-schema-design-json-schema.md 1.8 KB
- references/5-rest-api-to-mcp-pattern.md 5.7 KB
- references/6-three-tier-authentication.md 15 KB
- references/7-monetization-strategy.md 9.0 KB
- references/8-express-js-architecture.md 3.2 KB
- references/9-security.md 7.4 KB
- references/appendix-a-graceful-shutdown.md 519 B
- references/appendix-b-redis-rate-limiter-production.md 1.4 KB
- references/appendix-c-tool-registration-helper.md 1.4 KB
- references/quick-start.md 951 B
- references/tools.md 315 B
- references/when-to-use.md 483 B
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.
- 10d ago First seen · 39 lines · 95 tokens per session scan A ed710729889b
mcp-server-builder is a skill published in the GitHub repository san-npm/skills-ws (2 stars, last pushed 3d ago), licensed MIT. It adds 95 tokens to every session and 1,071 once invoked, about $0.0005 per session on Opus 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.
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