generated: '2026-08-09'
method: derived
source: mcp/lacuna-mcp-tools-list.json + openapi/lacuna-music-openapi-original.json
description: >-
  Binds every Lacuna MCP tool and A2A skill to its backing OpenAPI operation. The MCP tool input schemas
  were read live and anonymously from tools/list, so the bindings below were checked field-by-field
  against the OpenAPI request bodies rather than inferred from names.
surfaces:
  openapi:
    file: openapi/lacuna-music-openapi-original.json
    url: https://www.lacuna.fm/api/openapi.json
    operations: 2
    gated: false
  mcp:
    url: https://www.lacuna.fm/mcp
    transport: streamable-http
    tools_list_gated: false
    note: initialize + tools/list are anonymous; tools/call requires music:generate or an API key.
  a2a:
    url: https://www.lacuna.fm/a2a
    gated: true
    note: Every A2A method requires auth; an anonymous message/send returned 401.
  graphql: null
crosswalk:
  - tool: generate_music
    surface: mcp
    category: music-generation
    rest: [createGeneration]
    binding: rest
    confidence: high
    note: >-
      Input schema is a field-for-field match against the OpenAPI GenerateRequest — style, title,
      lyrics, instrumental, model, vocal_gender, negative_tags, style_weight, weirdness_constraint,
      audio_weight, required [style, title], additionalProperties false. One real divergence: the MCP
      model enum is [aether, echo] while the OpenAPI GenerateRequest enum also carries `nocturne`
      (180 credits, and marked in the spec as retained for backward compatibility and not recommended
      for new integrations). The MCP surface exposes the narrower, current model set.
  - tool: get_generation
    surface: mcp
    category: music-generation
    rest: [getGeneration]
    binding: rest
    confidence: high
    note: Single `id` string parameter, matching the OpenAPI path parameter.
  - skill: generate_music
    surface: a2a
    category: music-generation
    rest: [createGeneration, getGeneration]
    binding: rest
    confidence: medium
    note: >-
      The A2A skill is a composite — the card documents submit-then-poll via tasks/get, which maps onto
      both REST operations. It also accepts a plain text part that is treated as a style description and
      rendered instrumental, a coercion with no REST equivalent.
mcp_only:
  - tool: list_models
    reason: >-
      Returns the available music models with credit cost per task, tracks produced per task and
      language coverage. No public REST operation exposes a models catalog — the OpenAPI only documents
      the model enum inline on GenerateRequest and a credits table in the info description.
  - tool: wait_for_generation
    surface: stdio (npm lacuna-mcp)
    reason: >-
      Blocking poll helper published by the local stdio server (and named in the provider's Agent Skill)
      but absent from the hosted server's tools/list. Client-side composition over getGeneration, not a
      distinct API operation.
rest_only: []
divergences:
  - The hosted MCP server and the npm stdio server expose different tool sets (list_models vs wait_for_generation).
  - The `nocturne` model is in the OpenAPI enum but not in the MCP generate_music enum.
  - A2A exposes one coarse skill; MCP exposes three fine-grained tools over the same core.
coverage:
  tools_named: 3
  tools_bound_to_rest: 2
  mcp_only: 1
  a2a_skills: 1
  rest_operations_total: 2
  rest_operations_with_a_tool: 2