AINumbers.co Yield Curve API

openapi: 3.2.0
info:
  title: AINumbers.co Fintech Intelligence Suite Yield Curve API
  version: 1.0.0
  description: '**1255 fintech intelligence tools** covering ISO 20022, A2A payments, CFPB §1033, EU AI Act, DORA, MiCA, AML/KYC, BaaS, DLT/tokenization, ESG/climate finance, agentic payments (AP2, ACP, x402, Visa TAP, Mastercard Agent Pay), PQC migration, sanctions screening, and OpenChainGraph v0.4 computation chains.


    ## Transport


    > **The live transport is MCP JSON-RPC 2.0 at `https://mcp.ainumbers.co/mcp` — not REST.**

    >

    > This OpenAPI file is a **descriptive data-room artifact** — a machine-readable index of all tools and their input/output schemas. The REST paths (`POST /v1/tools/{name}`) described here are a projection; they become functional only if the optional REST shim (Area 2 Path B) is deployed.

    >

    > To call tools today, connect via the official MCP client SDKs. TypeScript: `@modelcontextprotocol/sdk`. Python: `mcp`.


    ## Architecture


    All tools run **entirely client-side** (browser JavaScript). Zero PII. Zero server calls after page load. Deterministic, reproducible outputs. Licensed CC BY 4.0.


    OpenChainGraph v0.4 compute-binding nodes additionally run **server-side on the MCP Worker** and emit verifiable artifacts with `execution_hash` (WebCrypto SHA-256 over RFC 8785 canonical JSON).'
  contact:
    name: Post Oak Labs
    url: https://postoaklabs.com
    email: tim@postoaklabs.com
  license:
    name: CC BY 4.0
    url: https://creativecommons.org/licenses/by/4.0/
servers:
- url: https://ainumbers.co
  description: Static browser-based tool host (DreamHost). Tools run client-side — no REST gateway is active on this origin. See x-mcp for the live MCP endpoint.
tags:
- name: yield_curve
paths:
  /v1/tools/build_yield_curve_gspread:
    post:
      operationId: build_yield_curve_gspread
      summary: Yield Curve & G-Spread
      description: 'Builds a par yield curve from caller-supplied benchmark points (at least 2, strictly increasing tenors; no live data) under a named, versioned interpolation, linear (linear@1) or monotone cubic Hermite with Fritsch-Carlson 1980 tangents (monotone_cubic_hermite@1), and reports the G-spread of a bond against that curve: the interpolated benchmark yield at the bond’s maturity and (bond yield minus benchmark yield) x 100 in basis points. A bond maturity outside the benchmark tenor range is refused naming the range, never extrapolated. Every assumption is named in plain sentences in the output.


        **Tool URL:** https://ainumbers.co/chaingraph/art-706-yield-curve-gspread.html

        **AP2/Policy Mandate export:** yes'
      tags:
      - yield_curve
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - benchmark_points
              - benchmark_name
              - bond
              properties:
                benchmark_points:
                  type: array
                  description: 'Caller-supplied benchmark points [{ tenor_years, yield_pct }]: at least 2, strictly increasing tenors, used exactly as given (no live data).'
                  items:
                    type: object
                    properties:
                      tenor_years:
                        type: number
                      yield_pct:
                        type: number
                benchmark_name:
                  type: string
                  description: Non-empty string naming the caller-supplied benchmark, echoed into the output curve.
                interpolation:
                  type: string
                  enum:
                  - linear
                  - monotone_cubic_hermite
                  description: 'Named interpolation: ''linear'' (linear@1) or ''monotone_cubic_hermite'' (monotone_cubic_hermite@1, Fritsch-Carlson 1980). Defaults to linear.'
                bond:
                  type: object
                  description: '{ maturity_years, yield_pct } of the bond. A maturity_years outside the benchmark tenor range is refused naming the range, never extrapolated.'
                  properties:
                    maturity_years:
                      type: number
                    yield_pct:
                      type: number
      responses:
        '200':
          description: Successful tool execution result
          content:
            application/json:
              schema:
                type: object
                properties:
                  assumptions:
                    type: array
                    items:
                      type: string
                  benchmark_yield_at_maturity_pct:
                    type:
                    - number
                    - 'null'
                  curve:
                    type:
                    - object
                    - 'null'
                  detail:
                    type: string
                  domain_errors:
                    type: array
                    items:
                      type: object
                      properties:
                        code:
                          type: string
                          enum:
                          - BENCHMARK_POINTS_TOO_FEW
                          - MATURITY_OUTSIDE_CURVE_RANGE
                          - TENORS_NOT_STRICTLY_INCREASING
                        text:
                          type: string
                      required:
                      - code
                      - text
                      additionalProperties: false
                  error:
                    type: string
                    enum:
                    - benchmark_points_too_few
                    - maturity_outside_curve_range
                    - tenors_not_strictly_increasing
                  g_spread_bp:
                    type:
                    - number
                    - 'null'
                  note:
                    type: string
                  regulatory_basis:
                    type: string
                required:
                - assumptions
                - benchmark_yield_at_maturity_pct
                - curve
                - g_spread_bp
                additionalProperties: false
                x-derived-from: fixture
      x-mcp-tool-name: build_yield_curve_gspread
      x-tool-url: https://ainumbers.co/chaingraph/art-706-yield-curve-gspread.html
      x-source: manifest
      x-ap2-export: true
x-mcp:
  transport: MCP JSON-RPC 2.0 (streamable HTTP)
  endpoint: https://mcp.ainumbers.co/mcp
  protocol_version: '2025-11-25'
  authentication: none
  registry: co.ainumbers/tools (official MCP registry)
  note: Connect any MCP-compatible client (Claude, ChatGPT, custom agent) directly to this endpoint. The REST paths in this file are descriptive only — they do not exist on the live server unless the REST shim is deployed.