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 Spi 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: Spi
paths:
  /v1/spi:
    post:
      description: 'Compute the Standardized Precipitation Index (McKee et al. 1993) at a cell: fit a gamma distribution to the same-window precipitation-accumulation history, then standardize the current accumulation to a z-score and map it to a drought class (extreme/severe/moderate drought … normal … wet). Supply `precip_history_mm` + `current_accumulation_mm` directly, or omit them to read the stored `weather.precipitation_mm` trajectory and build the window accumulations server-side. `window_days` selects SPI-1 (30 d), SPI-3 (90 d, default), SPI-12 (360 d), etc. The result is signed; the receipt cites the precipitation fact_cids it read from the shared memory.


        When to use: Call when the user asks ''is this place in drought'', ''how dry is it relative to normal'', or wants a precipitation-anomaly z-score. The response is honest: when fewer than the WMO-recommended minimum samples exist it returns verdict=`inconclusive` with `spi:null` and a `honest_note` rather than fabricating a z-score from a handful of points. Quote the `spi`, `spi_class`, and `n_samples`. For raw precipitation use `emem_weather`; SPI is the standardized anomaly.'
      operationId: emem_spi
      requestBody:
        content:
          application/json:
            schema:
              properties:
                cell:
                  description: cell64 or place name
                  type: string
                current_accumulation_mm:
                  description: Current-window accumulation (mm); required when precip_history_mm is supplied.
                  type: number
                precip_history_mm:
                  description: Optional explicit same-window precipitation accumulations (mm).
                  items:
                    type: number
                  type: array
                window_days:
                  description: Accumulation window (SPI-3 = 90 d default; SPI-1 = 30 d; SPI-12 = 360 d).
                  type: integer
              required:
              - cell
              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: 'McKee-1993 Standardized Precipitation Index drought metric: fits a gamma to the…'
      tags:
      - Spi
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