generated: '2026-08-09'
method: searched
source: openapi/cyclecalcs-astronomy-openapi-original.json
docs:
  - https://www.cyclecalcs.com/api/keys.html
  - https://www.cyclecalcs.com/api/mcp.html
description: >-
  CycleCalcs issues no API keys of its own and no request to
  www.cyclecalcs.com needs one. The direct /v2 API is keyless: every request,
  from anyone, is served at the free Basic tier. The paid tiers are sold
  through the RapidAPI marketplace and authenticate at RapidAPI's gateway
  host, never at the origin. The MCP server is the one surface that does
  require a credential — and only to invoke a tool, not to browse one.
summary:
  types:
  - none          # the direct REST API accepts no credential
  - apiKey        # at the RapidAPI gateway, and on the MCP server
  api_key_in:
  - header
  oauth2_flows: []
  keyless_tier: true
  signup_required: false
schemes:
- name: none
  type: none
  surface: https://www.cyclecalcs.com/v2
  description: >-
    No account, no signup, no header, no key to rotate. Every direct request
    is served at the free Basic tier whoever sends it. Open CORS, so the API
    is callable straight from a browser.
  sources:
  - https://www.cyclecalcs.com/api/keys.html
- name: RapidAPIKey
  type: apiKey
  in: header
  parameter: X-RapidAPI-Key
  surface: https://cyclecalcs-astronomy-api3.p.rapidapi.com
  description: >-
    Read only by the RapidAPI gateway host, never by the origin declared in
    the OpenAPI `servers` block. A key raises the caller's limits to the
    subscribed tier and is what monthly volume is metered against. Sold at
    https://rapidapi.com/info-8KZIhinZ9/api/cyclecalcs-astronomy-api3.
  sources:
  - openapi/cyclecalcs-astronomy-openapi-original.json
- name: MCPBearer
  type: http
  scheme: bearer
  surface: https://www.cyclecalcs.com/mcp
  parameter: Authorization
  description: >-
    `Authorization: Bearer <RapidAPI key>` on every MCP tool call. The tool
    call is forwarded through the RapidAPI gateway with that key, so it meters
    exactly as a direct REST call would.
  sources:
  - https://www.cyclecalcs.com/api/mcp.html
- name: MCPApiKeyHeader
  type: apiKey
  in: header
  parameter: X-Api-Key
  surface: https://www.cyclecalcs.com/mcp
  description: >-
    Equally supported alternative to the Bearer header, sent as a raw value
    with no prefix. It exists because some directories and gateways reserve
    Authorization for their own sign-in and can only forward a differently
    named header.
  sources:
  - https://www.cyclecalcs.com/api/mcp.html
anonymous_surfaces:
  - surface: https://www.cyclecalcs.com/v2 (all 29 operations)
    note: fully anonymous, free Basic tier
  - surface: https://www.cyclecalcs.com/mcp — initialize + tools/list
    note: >-
      Browsing the MCP server needs no key. A client, inspector or directory
      can read all eleven tool schemas before anyone has signed up.
  - surface: https://www.cyclecalcs.com/mcp — tools/call
    note: >-
      Requires a key. A call without one is refused as a normal tool result
      carrying instructions, not an HTTP 401 that would drop the connection.
credential_hygiene:
  key_in_url: never accepted
  ignored_parameter: >-
    A `key=` query parameter is recognised and deliberately IGNORED — the
    request is served at the tier of its entrance and earns a
    `parameter_ignored` warning naming exactly that. "A credential never
    belongs in a URL: URLs are logged, cached and shared in ways headers are
    not."
  reserved_error_codes: [INVALID_KEY, REVOKED_KEY, EXPIRED_KEY]
  reserved_note: >-
    Reserved in the error registry for a direct key channel if one ever ships,
    so shipping it would change nothing else about how errors are structured.
    None is reachable today.
what_a_subscription_buys:
  - a higher rate limit in the same windows
  - a higher per-request range ceiling
  - "nothing else: no extra endpoint, no different data, no different answer"
tier_reporting:
  field: caller_tier
  where: /v2/conventions
  note: The tier a request was actually served at is always checkable.