> ## Documentation Index > Fetch the complete documentation index at: https://docs.hyphaedb.com/llms.txt > Use this file to discover all available pages before exploring further. # Store a knowledge cell > Store a single cell of knowledge and return its node id. Validation, quota, and authorization run inside the facade. `source_agent` and `tenant_id` are stamped from the authenticated principal and cannot be set by the client. ## OpenAPI ````yaml /api-reference/openapi.json post /v1/store openapi: 3.0.3 info: title: HyphaeDB REST API version: 1.0.0 description: >- The unary REST surface over the HyphaeDB internal service facade. JSON over HTTP/1.1; every endpoint is a thin translator onto the same facade that gRPC and MCP speak. `recall` and `query` return fully hydrated nodes in rank order (nearest-first); no similarity score rides the wire — the array order conveys the rank. All endpoints except `GET /healthz` require an API key supplied in the `x-hyphae-key` header. Errors use a uniform envelope: `{ "error": { "code": string, "message": string } }`. This document covers the unary REST endpoints only. The WebSocket gossip stream (`GET /v1/inbox`) and the MCP-over-HTTP endpoint (`POST /mcp`) are separate surfaces not described here, and `GET /openapi.json` serves this document itself. servers: - url: http://localhost:8080 description: Local HyphaeDB server security: - ApiKeyAuth: [] tags: - name: Memory description: Store and retrieve knowledge cells. - name: Sessions description: Open and close working sessions. - name: Beacons description: Standing interest beacons for gossip routing. - name: Inbox description: 'The gossip inbox: the unary work-cycle drain for non-resident agents.' - name: Scenes description: Scene listing, lookup, and consolidation. - name: Health description: Liveness probe. paths: /v1/store: post: tags: - Memory summary: Store a knowledge cell description: >- Store a single cell of knowledge and return its node id. Validation, quota, and authorization run inside the facade. `source_agent` and `tenant_id` are stamped from the authenticated principal and cannot be set by the client. operationId: store requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/StoreBody' responses: '200': description: The stored cell's node id. content: application/json: schema: $ref: '#/components/schemas/StoreResponse' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '409': $ref: '#/components/responses/Conflict' '415': $ref: '#/components/responses/UnsupportedMediaType' '422': $ref: '#/components/responses/UnprocessableContent' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/ServerError' '503': $ref: '#/components/responses/Unavailable' components: schemas: StoreBody: type: object description: The body for `POST /v1/store`. required: - content - cell_type properties: content: type: string description: The cell's text content. cell_type: $ref: '#/components/schemas/CellType' salience: type: number format: float default: 0.5 minimum: 0 maximum: 1 description: >- Importance hint in [0.0, 1.0]; the server clamps out-of-range values. scene_id: type: string format: uuid description: An optional owning scene id. source_ref: $ref: '#/components/schemas/SourceRef' metadata: type: object additionalProperties: true default: {} description: Arbitrary JSON metadata; defaults to an empty object. idempotency_key: type: string description: An optional key to deduplicate retried stores. StoreResponse: type: object required: - node_id properties: node_id: type: string format: uuid description: The stored cell's node id. CellType: type: string description: >- The nine cell types the energy and promotion models are calibrated against. enum: - Decision - Constraint - Risk - Pattern - Lesson - Fact - Preference - Context - Task SourceRef: type: object description: >- A reference back to the source of a cell's content (e.g. `file:line`, `url`). required: - kind - locator properties: kind: type: string description: The reference kind, e.g. `file` or `url`. locator: type: string description: The locator within that kind, e.g. a path or URL. Error: type: object description: The uniform error envelope returned for every non-2xx response. required: - error properties: error: type: object required: - code - message properties: code: type: string description: A stable, machine-readable error code. enum: - not_found - validation - dimension_mismatch - unauthorized - forbidden - conflict - transaction - quota_exceeded - rate_limited - timeout - unavailable - storage - embedding - config - internal message: type: string description: >- A redaction-safe, human-readable description (never embeds secrets). responses: BadRequest: description: >- The request was malformed or failed validation (codes: `validation`, `dimension_mismatch`). content: application/json: schema: $ref: '#/components/schemas/Error' Unauthorized: description: 'Missing or invalid `x-hyphae-key` (code: `unauthorized`).' content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: 'Authenticated but not permitted (code: `forbidden`).' content: application/json: schema: $ref: '#/components/schemas/Error' Conflict: description: 'A conflicting or aborted operation (codes: `conflict`, `transaction`).' content: application/json: schema: $ref: '#/components/schemas/Error' UnsupportedMediaType: description: >- The request body was sent with a non-JSON `Content-Type` (code: `validation`). Send `Content-Type: application/json`. content: application/json: schema: $ref: '#/components/schemas/Error' UnprocessableContent: description: >- The JSON body parsed but did not match the expected shape — a missing required field or a wrong field type (code: `validation`). content: application/json: schema: $ref: '#/components/schemas/Error' RateLimited: description: >- Quota exhausted or rate limited (codes: `quota_exceeded`, `rate_limited`). A `rate_limited` response sets the `Retry-After` header (in seconds). headers: Retry-After: description: Seconds to wait before retrying (only on `rate_limited`). schema: type: integer minimum: 1 content: application/json: schema: $ref: '#/components/schemas/Error' ServerError: description: 'An internal error (codes: `embedding`, `config`, `internal`).' content: application/json: schema: $ref: '#/components/schemas/Error' Unavailable: description: 'A dependency was unavailable (codes: `unavailable`, `storage`).' content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-hyphae-key description: >- The API key issued for the calling agent. Required on every endpoint except `GET /healthz`. ````