openapi: 3.2.0
info:
  description: emem is shared memory for AI agents working together in the real world.
  license:
    name: Apache-2.0
  title: emem Region Similarity API
  version: 2.4.0
  x-emem-surface-asymmetry:
    memory_notes: MCP only
    reach_them_at: POST /mcp, method tools/call
    read_side_is_here:
    - /v1/memory/search
    - /v1/memory/sse
    - /memories/{path}
    tools:
    - emem_memory_create
    - emem_memory_view
    - emem_memory_delete
    - emem_memory_rename
    - emem_memory_str_replace
    - emem_memory_supersede
    why_not_here: These write the agent correspondence plane, which is prose and untrusted-by-declaration. It is deliberately not part of the REST fact surface, and the two planes are kept apart rather than merged for convenience.
servers:
- description: Hosted instance (HTTPS-only)
  url: https://emem.dev
tags:
- name: Region Similarity
paths:
  /v1/region_similarity:
    post:
      description: 'Answer ''how alike are these two places?'' Mean-pool the 128-D GeoTessera embedding across each region''s cells to get a centroid, then return the cosine similarity in [-1,1] (+1 = identical landscape, 0 = unrelated). Each region is {place} | {polygon_bbox} | {cells}. CPU-fetched embeddings, no GPU sidecar needed. Surfaces how many cells in each region actually carried a vector (coverage).


        When to use: Call to compare two areas at the level of overall land character (e.g. ''is this valley like that one?'', ''find me somewhere that looks like X''). Degrades to a signed `inconclusive` (no number) when a region has no embedding-covered cells. For a single cell-to-cell vector cosine use `emem_compare`; for k-NN retrieval use `emem_find_similar`.'
      operationId: emem_region_similarity
      requestBody:
        content:
          application/json:
            schema:
              properties:
                max_cells:
                  default: 64
                  maximum: 256
                  minimum: 1
                  type: integer
                region_a:
                  description: '{place} | {polygon_bbox:{min_lat,max_lat,min_lng,max_lng}} | {cells:[cell64,...]}'
                  type: object
                region_b:
                  description: same shape as region_a
                  type: object
              required:
              - region_a
              - region_b
              type: object
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                type: object
          description: ok
        default:
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorEnvelope'
          description: 'error, the emem.error.v1 envelope. Branch on the stable `code` (see GET /v1/errors), not the message. A malformed or missing-field request body returns `code: invalid_argument` with the offending field named in `message`.'
      summary: How alike are two places?
      tags:
      - Region Similarity
components:
  schemas:
    ErrorEnvelope:
      description: The `emem.error.v1` failure envelope returned by every endpoint on a 4xx/5xx. Branch on the stable `code` (not the human `message`). See GET /v1/errors for the full code catalog.
      properties:
        code:
          description: Stable machine-readable error code. One of the codes in GET /v1/errors.
          example: invalid_argument
          type: string
        details:
          description: Optional structured recovery hints; present on errors that ship machine-readable next-steps.
          type: object
        message:
          description: Human-readable detail. For invalid_argument this names the offending field (e.g. "missing field `q`").
          type: string
        path:
          description: Request path that produced the error.
          example: /v1/ask
          type: string
        schema:
          const: emem.error.v1
          type: string
      required:
      - code
      - message
      - schema
      type: object