emem Band Composite API

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 Band Composite 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: Band Composite
paths:
  /v1/band_composite:
    post:
      description: 'Mint a signed, cloud-masked median composite over a date window as a raster-shaped field: the clean, gap-filled texture a world model actually drapes, rather than one cloudy scene. It reads every Sentinel-2 scene in [start_date, end_date] over the bbox, masks each per pixel by its SCL scene-classification class (default reject {0,1,3,8,9,10}: no-data, saturated, cloud shadow, cloud, cirrus; snow 11 is KEPT because snow is surface, not occlusion, and a snow-rejected median would fabricate a bare winter scene; override with mask_policy), and takes the per-pixel lower-of-two median (never averaging two measurements into a value nobody took) with a pinned min_valid_count, below which a pixel is nodata. The mask policy, min_valid_count, and the exact member scene list are pinned in the signed derivation, so a stranger re-derives the composite pixel for pixel from the same scenes. Returns an emem:raster: token (resolve with emem_raster_resolve) plus the content-addressed artifact; the receipt binds (aoi_cid, derivation_cid). Needs at least two clear scenes at one CRS. This signs and persists the derivation.


        When to use: Call when a world model or an analyst needs the clean composite texture over an area across a season, not a single-date snapshot that may be cloudy: a scrub-frame base layer, a gap-filled band drape, a cloud-free mosaic. For one pinned scene use emem_band_raster; for the per-slice time series use emem_band_cube.'
      operationId: emem_band_composite
      requestBody:
        content:
          application/json:
            schema:
              properties:
                band:
                  description: s2.B02|s2.B03|s2.B04|s2.B08|s2.B11|s2.B12
                  type: string
                bbox:
                  properties:
                    max_lat:
                      type: number
                    max_lng:
                      type: number
                    min_lat:
                      type: number
                    min_lng:
                      type: number
                  required:
                  - min_lat
                  - min_lng
                  - max_lat
                  - max_lng
                  type: object
                end_date:
                  description: YYYY-MM-DD inclusive
                  type: string
                mask_policy:
                  description: SCL classes to reject per pixel; default [0,1,3,8,9,10]
                  items:
                    type: integer
                  type: array
                max_scenes:
                  description: cap on scenes read; default 12
                  maximum: 16
                  minimum: 2
                  type: integer
                min_valid_count:
                  description: per-pixel minimum valid samples for a value, else nodata; default 1
                  minimum: 1
                  type: integer
                start_date:
                  description: YYYY-MM-DD inclusive
                  type: string
              required:
              - bbox
              - band
              - start_date
              - end_date
              type: object
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                type: object
          description: ok
        '400':
          content:
            application/json:
              schema:
                properties:
                  details:
                    type: object
                  error:
                    type: string
                type: object
          description: invalid argument; `details.code` names which rule refused
        '502':
          description: upstream scene fetch failed; typed
        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: a signed, cloud-masked median composite over a date window, as a raster-shaped…
      tags:
      - Band Composite
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