Toolsmith

Forge MCP tools and Agent Skills from your OpenAPI. — toolsmith.apicommons.org

An OpenAPI tells developers what your API can do. Agents need more. Toolsmith is a browser-first workbench for designing the agent layer of an API: load any OpenAPI (the API Evangelist and APIs.io APIs are one click away), then design — for every operation — a rich MCP tool with an honest input schema and behavior annotations, the resources and prompts that give it context, sampling guidance where the server should lean on the client's model, and one or more Agent Skills that teach an agent to apply the tool competently.

How it works

• The enriched OpenAPI is the artifact of record. Your designs are stored inside the document itself as x-mcp (tool, resources, prompts, sampling) and x-agent-skills extensions on each operation, plus an x-mcp-server block at the root. Edit the raw OpenAPI on the source tab any time — the designs travel with it.
• Draft, then refine. "Draft all" (or per-operation drafting) deterministically seeds each design from what the contract already knows: tool input schemas from parameters and request bodies, behavior annotations from HTTP method semantics, a starter prompt, and a skill scaffold per tool — plus a spec-wide overview skill that indexes the whole tool surface. No AI calls — everything runs in your browser and nothing leaves the page.
• API-level skills. Skills aren't only per-operation: the API-level entry at the top of the operation list holds spec-wide skills — the overview, cross-cutting conventions (auth, pagination, rate limits), troubleshooting playbooks — stored as root-level x-agent-skills.
• Checks. A lint pass validates the whole design against the specs: MCP tool-name rules and uniqueness, input-schema consistency, annotation sanity (read-only vs destructive vs method), resource URIs, prompt integrity, registry server.json shape (reverse-DNS name, semver, https remotes), and every Agent Skills frontmatter constraint (name pattern, description/compatibility caps, body guidance). Click a finding to jump to it.
• Export the whole layer:
  • the enriched OpenAPI (YAML with the extensions embedded)
  • an MCP server design — tools, resources, prompts, and sampling in the shapes MCP clients see
  • a registry-ready server.json (2025-09-29 schema) for the official MCP Registry
  • an Agent Skills bundle — one SKILL.md per skill, zipped by directory, with an agent-skills-discovery v0.2.0 index.json ready for .well-known/agent-skills/
  • a runnable MCP server — a complete TypeScript project (official @modelcontextprotocol/sdk, stdio) where every tool proxies to its real OpenAPI operation with path/query/header/body mapping and auth derived from the spec's security scheme; npm install && npm run dev and it serves. The runtime is static; only the operation data is generated, so you can regenerate as the design evolves.
  • the APIs.json properties that wire the artifacts to your provider listing

Develop

npm install
npm run dev     # local dev server
npm run build   # production build to dist/

Deployed to GitHub Pages by .github/workflows/pages.yml on push to main.

Part of the API Commons tool suite. Pairs with Context Gate (govern what agents consume) and the API Validator.

License

Apache-2.0