api2skill 0.4.3

api2skill

Convert an OpenAPI/Swagger document into a self-contained Claude Agent Skill — a SKILL.md plus a runnable dispatcher script — so an existing REST API becomes something Claude can call correctly, with authentication, without you hand-writing the wrapper.

api2skill generate ./petstore.json
# -> ./swagger-petstore/
#      SKILL.md               # compact overview + auth setup + operation index
#      reference/<tag>.md     # full per-operation detail, loaded on demand
#      scripts/call.cs        # the dispatcher (.cs by default; --script fsx|csx also available)
#      secrets.example.json   # template — copy to secrets.json and fill in real credentials
#      .api2skill.json        # generation manifest — records options for `update`
#      .gitignore             # excludes secrets.json

Drop the output directory into ~/.claude/skills/ (or a project's .claude/skills/) and Claude can use it immediately.

Full documentation: wiki/Home.md — getting started, CLI reference, authentication, and Mermaid diagrams. Docs live in this repo under wiki/; see wiki/README.md for how to browse them.

Why

Writing a correct, well-documented Claude Skill for an API by hand is repetitive: endpoint and parameter docs, auth handling, and example requests all have to be derived from the API's own OpenAPI spec anyway. api2skill automates that derivation.

Install

Requires the .NET 10 SDK.

dotnet tool install --global api2skill

Or build from source (this repo pins the SDK version via global.json):

dotnet build --configuration Release
dotnet run --project src/Api2Skill -- generate <spec> [options]

Quickstart

# From a local file
api2skill generate ./petstore.json

# From a running service (self-signed dev cert: add --insecure)
api2skill generate https://svc.local/swagger.json --insecure

# Custom name and output path — options are recorded in .api2skill.json
api2skill generate ./petstore.json --name my-petstore --out ./skills/my-petstore

# Refresh when the spec changes (reuses saved --script/--include/--out from manifest)
api2skill update ./skills/my-petstore ./petstore-v2.json
api2skill update ./skills/my-petstore   # re-fetch original spec source

# Rename or relocate while updating (secrets.json, auth.json, .auth-cache.json move with it)
api2skill update ./skills/my-petstore ./petstore-v2.json --name petstore-prod --out ./apis/petstore

Then, inside the generated skill directory:

cp secrets.example.json secrets.json   # fill in real credentials
dotnet run scripts/call.cs -- getPetById --petId 3

Authentication (basics)

# Quick bearer token scaffold
api2skill generate ./api.json --auth bearer

# Auto-scaffold auth.json from OpenAPI security schemes (first generate, no --auth flags)
api2skill generate ./api.json --out ./my-skill
# → ./my-skill/auth.json (inactive template) + SKILL.md "Auth profile names" section
# Activate after editing:
api2skill generate ./api.json --auth-config ./my-skill/auth.json --force --out ./my-skill

# Full auth config (OAuth2, Entra, script commands, custom headers)
api2skill generate ./api.json --auth-config ./auth.json --login

--auth and --auth-config are mutually exclusive. See wiki/Authentication.md for profile types, Entra preset, and script auth examples.

Project layout

src/Api2Skill/       the generator (console app)
tests/Api2Skill.Tests/   xUnit — unit, golden, and integration tests
wiki/                in-repo documentation (start at wiki/Home.md)
specs/               feature specs (Spec Kit)

Status

MVP complete: three script emitters (cs/fsx/csx), explicit auth (bearer, basic, custom, script, OAuth2/Entra), generate and update commands, filtering, and atomic output staging. See specs/001-openapi-to-skill/spec.md for milestone scope.