openapi: 3.0.3
info:
  title: Letta Agent Templates API
  description: The Letta API creates and operates stateful AI agents whose memory - core context blocks and archival vector memory - persists across sessions. It configures the tools, data sources, identities, and multi-agent groups an agent uses, sends and streams messages to agents, and inspects the runs, jobs, and steps behind every agent response. The same OpenAPI-documented interface is served by the managed Letta Cloud API and by the open-source, self-hostable Letta server. All requests require a Bearer API key.
  version: 1.0.0
  contact:
    name: Letta
    url: https://www.letta.com
  license:
    name: Apache-2.0
    url: https://github.com/letta-ai/letta/blob/main/LICENSE
servers:
- url: https://api.letta.com/v1
  description: Letta Cloud
- url: http://localhost:8283/v1
  description: Self-hosted (default local port)
security:
- bearerAuth: []
tags:
- name: Agent Templates
  description: Cloud-only versioned agent configuration templates.
paths:
  /v1/templates:
    get:
      tags:
      - Agent Templates
      summary: List templates (Cloud-only)
      description: List all templates
      parameters:
      - name: offset
        in: query
        required: false
        schema:
          type: string
      - name: exact
        in: query
        required: false
        description: Whether to search for an exact name match
        schema:
          type: string
      - name: limit
        in: query
        required: false
        schema:
          type: string
      - name: version
        in: query
        required: false
        description: Specify the version you want to return, otherwise will return the latest version
        schema:
          type: string
      - name: template_id
        in: query
        required: false
        schema:
          type: string
      - name: name
        in: query
        required: false
        schema:
          type: string
      - name: search
        in: query
        required: false
        schema:
          type: string
      - name: project_slug
        in: query
        required: false
        schema:
          type: string
      - name: project_id
        in: query
        required: false
        schema:
          type: string
      - name: sort_by
        in: query
        required: false
        schema:
          type: string
          enum:
          - updated_at
          - created_at
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Template'
        '401':
          $ref: '#/components/responses/Unauthorized'
    post:
      tags:
      - Agent Templates
      summary: Create template (Cloud-only)
      description: Creates a new template from an existing agent or agent file
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '401':
          $ref: '#/components/responses/Unauthorized'
        '422':
          $ref: '#/components/responses/ValidationError'
  /v1/templates/{project_id}:
    post:
      tags:
      - Agent Templates
      summary: Create template (Cloud-only)
      description: Creates a new template from an existing agent or agent file
      parameters:
      - name: project_id
        in: path
        required: true
        description: The project id
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '422':
          $ref: '#/components/responses/ValidationError'
  /v1/templates/{project_id}/{name}/versions:
    get:
      tags:
      - Agent Templates
      summary: List template versions (Cloud-only)
      description: List all versions of a specific template
      parameters:
      - name: project_id
        in: path
        required: true
        description: The project id
        schema:
          type: string
      - name: name
        in: path
        required: true
        description: The template name (without version)
        schema:
          type: string
      - name: offset
        in: query
        required: false
        schema:
          type: string
      - name: limit
        in: query
        required: false
        schema:
          type: string
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                additionalProperties: true
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
  /v1/templates/{project_id}/{template_version}/agents:
    post:
      tags:
      - Agent Templates
      summary: Create Agents From Template
      description: Creates an Agent or multiple Agents from a template
      parameters:
      - name: project_id
        in: path
        required: true
        description: The project id
        schema:
          type: string
      - name: template_version
        in: path
        required: true
        description: The template version, formatted as {template-name}:{version-number} or {template-name}:latest. This endpoint is not available for self-hosted Letta.
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              additionalProperties: true
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/AgentState'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '422':
          $ref: '#/components/responses/ValidationError'
components:
  schemas:
    Template:
      type: object
      description: A Cloud-only versioned agent configuration used to deploy new agents.
      properties:
        name:
          type: string
        project_id:
          type: string
        version:
          type: integer
        agent_id:
          type: string
        created_at:
          type: string
          format: date-time
        updated_at:
          type: string
          format: date-time
    HTTPValidationError:
      type: object
      properties:
        detail:
          type: array
          items:
            type: object
            properties:
              loc:
                type: array
                items:
                  type: string
              msg:
                type: string
              type:
                type: string
    AgentState:
      type: object
      description: A Letta stateful agent, including its memory, tools, sources, and model configuration.
      properties:
        id:
          type: string
          example: agent-123e4567-e89b-42d3-8456-426614174000
        name:
          type: string
        agent_type:
          type: string
        system:
          type: string
        description:
          type: string
        model:
          type: string
        embedding:
          type: string
        llm_config:
          type: object
          additionalProperties: true
        embedding_config:
          type: object
          additionalProperties: true
        memory:
          type: object
          additionalProperties: true
        blocks:
          type: array
          items:
            type: object
            additionalProperties: true
        tools:
          type: array
          items:
            type: object
            additionalProperties: true
        sources:
          type: array
          items:
            type: object
            additionalProperties: true
        tags:
          type: array
          items:
            type: string
        created_at:
          type: string
          format: date-time
        updated_at:
          type: string
          format: date-time
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            message:
              type: string
            code:
              type: string
  responses:
    Unauthorized:
      description: Missing or invalid Bearer API key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: The requested resource was not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    ValidationError:
      description: The request payload failed validation.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/HTTPValidationError'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'API key created at https://app.letta.com/api-keys, passed as `Authorization: Bearer YOUR_API_KEY`.'