Letta Internal Agents API

openapi: 3.1.0
info:
  title: Letta Admin Internal Agents API
  version: 1.0.0
  description: REST API for Letta, the stateful agents platform. Manage agents, memory blocks, archival passages, sources, custom tools, MCP servers, multi-agent groups, runs, and streaming responses. Available as Letta Cloud (managed) at https://api.letta.com/v1 and as the self-hosted open-source server (Apache-2.0) typically run at http://localhost:8283.
  contact:
    name: Letta
    url: https://www.letta.com/
    email: support@letta.com
  license:
    name: Apache-2.0
    url: https://github.com/letta-ai/letta/blob/main/LICENSE
  x-logo:
    url: https://www.letta.com/favicon.ico
servers:
- url: https://api.letta.com
  description: Letta Cloud (managed)
- url: https://app.letta.com
  description: Letta Cloud (app)
- url: http://localhost:8283
  description: Self-hosted Letta server
security:
- bearerAuth: []
tags:
- name: Internal Agents
  description: Internal Agents operations.
paths:
  /v1/_internal_agents/count:
    get:
      tags:
      - Internal Agents
      summary: Count Agents
      description: Get the total number of agents for a user, with option to exclude hidden agents.
      operationId: count_internal_agents
      parameters:
      - name: exclude_hidden
        in: query
        required: false
        schema:
          type: boolean
          description: If True, excludes hidden agents from the count. If False, includes all agents.
          default: true
          title: Exclude Hidden
        description: If True, excludes hidden agents from the count. If False, includes all agents.
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: integer
                title: Response Count Internal Agents
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
  /v1/_internal_agents/{agent_id}/core-memory/blocks/{block_label}:
    patch:
      tags:
      - Internal Agents
      summary: Modify Block for Agent
      description: Updates a core memory block of an agent.
      operationId: modify_internal_core_memory_block
      parameters:
      - name: block_label
        in: path
        required: true
        schema:
          type: string
          title: Block Label
      - name: agent_id
        in: path
        required: true
        schema:
          type: string
          minLength: 42
          maxLength: 42
          pattern: ^agent-[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$
          description: The ID of the agent in the format 'agent-<uuid4>'
          examples:
          - agent-123e4567-e89b-42d3-8456-426614174000
          title: Agent Id
        description: The ID of the agent in the format 'agent-<uuid4>'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/BlockUpdate'
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Block'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
components:
  schemas:
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
            - type: string
            - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
      type: object
      required:
      - loc
      - msg
      - type
      title: ValidationError
    Block:
      properties:
        value:
          type: string
          title: Value
          description: Value of the block.
        limit:
          type: integer
          title: Limit
          description: Character limit of the block.
          default: 100000
        project_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Project Id
          description: The associated project id.
        template_name:
          anyOf:
          - type: string
          - type: 'null'
          title: Template Name
          description: Name of the block if it is a template.
        is_template:
          type: boolean
          title: Is Template
          description: Whether the block is a template (e.g. saved human/persona options).
          default: false
        template_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Template Id
          description: The id of the template.
        base_template_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Base Template Id
          description: The base template id of the block.
        deployment_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Deployment Id
          description: The id of the deployment.
        entity_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Entity Id
          description: The id of the entity within the template.
        preserve_on_migration:
          anyOf:
          - type: boolean
          - type: 'null'
          title: Preserve On Migration
          description: Preserve the block on template migration.
          default: false
        label:
          anyOf:
          - type: string
          - type: 'null'
          title: Label
          description: Label of the block (e.g. 'human', 'persona') in the context window.
        read_only:
          type: boolean
          title: Read Only
          description: Whether the agent has read-only access to the block.
          default: false
        description:
          anyOf:
          - type: string
          - type: 'null'
          title: Description
          description: Description of the block.
        metadata:
          anyOf:
          - additionalProperties: true
            type: object
          - type: 'null'
          title: Metadata
          description: Metadata of the block.
          default: {}
        hidden:
          anyOf:
          - type: boolean
          - type: 'null'
          title: Hidden
          description: If set to True, the block will be hidden.
        id:
          type: string
          pattern: ^block-[a-fA-F0-9]{8}
          title: Id
          description: The human-friendly ID of the Block
          examples:
          - block-123e4567-e89b-12d3-a456-426614174000
        created_by_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Created By Id
          description: The id of the user that made this Block.
        last_updated_by_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Last Updated By Id
          description: The id of the user that last updated this Block.
        tags:
          anyOf:
          - items:
              type: string
            type: array
          - type: 'null'
          title: Tags
          description: The tags associated with the block.
          default: []
      type: object
      required:
      - value
      title: Block
      description: A Block represents a reserved section of the LLM's context window.
    BlockUpdate:
      properties:
        value:
          anyOf:
          - type: string
          - type: 'null'
          title: Value
          description: Value of the block.
        limit:
          anyOf:
          - type: integer
          - type: 'null'
          title: Limit
          description: Character limit of the block.
        project_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Project Id
          description: The associated project id.
        template_name:
          anyOf:
          - type: string
          - type: 'null'
          title: Template Name
          description: Name of the block if it is a template.
        is_template:
          type: boolean
          title: Is Template
          description: Whether the block is a template (e.g. saved human/persona options).
          default: false
        template_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Template Id
          description: The id of the template.
        base_template_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Base Template Id
          description: The base template id of the block.
        deployment_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Deployment Id
          description: The id of the deployment.
        entity_id:
          anyOf:
          - type: string
          - type: 'null'
          title: Entity Id
          description: The id of the entity within the template.
        preserve_on_migration:
          anyOf:
          - type: boolean
          - type: 'null'
          title: Preserve On Migration
          description: Preserve the block on template migration.
          default: false
        label:
          anyOf:
          - type: string
          - type: 'null'
          title: Label
          description: Label of the block (e.g. 'human', 'persona') in the context window.
        read_only:
          type: boolean
          title: Read Only
          description: Whether the agent has read-only access to the block.
          default: false
        description:
          anyOf:
          - type: string
          - type: 'null'
          title: Description
          description: Description of the block.
        metadata:
          anyOf:
          - additionalProperties: true
            type: object
          - type: 'null'
          title: Metadata
          description: Metadata of the block.
          default: {}
        hidden:
          anyOf:
          - type: boolean
          - type: 'null'
          title: Hidden
          description: If set to True, the block will be hidden.
        tags:
          anyOf:
          - items:
              type: string
            type: array
          - type: 'null'
          title: Tags
          description: The tags to associate with the block.
      type: object
      title: BlockUpdate
      description: Update a block
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer