How AI is applied across API Evangelist and APIs.io. Read my AI disclosure →
API Evangelist API Evangelist
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC

Letta Internal Agents API

Internal Agents operations.

Letta Internal Agents API is one of 41 APIs that Letta publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

This API exposes 14 JSON Schema definitions.

Tagged areas include Internal Agents. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, pricing, a changelog, and 14 JSON Schemas.

This API exposes 2 operations across 2 paths, and defines 4 schemas. It is described by OpenAPI 3.1.0, at version 1.0.0.

Requests are made against 3 base URLs: https://api.letta.com, https://app.letta.com, http://localhost:8283.

2 operations 2 paths 4 schemas 1 GET1 PATCH

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.1.0
API Version
1.0.0
Base URL
https://api.letta.com
Authentication
HTTP Bearer
Contact
License
Resource Areas
1

Authentication & Security 1

Letta Internal Agents API declares 1 security scheme for authenticating requests. It accepts HTTP bearer tokens (bearerAuth). By default, every request must be authenticated.

Paths & Operations 2

Across 2 paths, the API surfaces 2 operations — 1 GET, 1 PATCH. Each is listed below with its method, path, parameters, and response codes.

Internal Agents 2

Internal Agents operations.

GET
/v1/_internal_agents/count
Count Agents
count_internal_agents 1 param → 200422
PATCH
/v1/_internal_agents/{agent_id}/core-memory/blocks/{block_label}
Modify Block for Agent
modify_internal_core_memory_block 2 params body → 200422

Schemas 4

The contract defines 4 schemas that model the data the API accepts and returns. The most detailed are Block (19 properties), BlockUpdate (16 properties), ValidationError (3 properties), HTTPValidationError (1 property). Each schema is shown below with its type and property counts.

ValidationError
object
3 properties 3 required
Block
object
A Block represents a reserved section of the LLM's context window.
19 properties 1 required
BlockUpdate
object
Update a block
16 properties
HTTPValidationError
object
1 property

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

letta-internal-agents-api-openapi.yml Raw ↑

Other APIs Letta publishes across the network.

Letta Code
Letta Admin API
Letta Agents API
Letta Archives API
Letta Blocks API
Letta Chat API
Letta Client-Side Access Tokens API
Letta Conversations API
Letta Device Storage API
Letta Embeddings API
Letta Environments API
Letta Feeds API
Where this information came from

This is an independent, third-party profile of Letta Internal Agents API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.

Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.

info@apievangelist.com · Read the full data-sourcing policy →
On a security or compliance team? Put security in the subject line and you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.