API Reference

Tools

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Upsert Tool

put/v1/tools/

Create or update a tool

Body ParametersExpand Collapse

source_code: string

The source code of the function.

args_json_schema: optional map[unknown]

The args JSON schema of the function.

default_requires_approval: optional boolean

Whether or not to require approval before executing this tool.

description: optional string

The description of the tool.

enable_parallel_execution: optional boolean

If set to True, then this tool will potentially be executed concurrently with other tools. Default False.

json_schema: optional map[unknown]

The JSON schema of the function (auto-generated from source_code if not provided)

npm_requirements: optional array of NpmRequirement { name, version }

Optional list of npm packages required by this tool.

name: string

Name of the npm package.

minLength1

version: optional string

Optional version of the package, following semantic versioning.

pip_requirements: optional array of PipRequirement { name, version }

Optional list of pip packages required by this tool.

name: string

Name of the pip package.

minLength1

version: optional string

Optional version of the package, following semantic versioning.

return_char_limit: optional number

The maximum number of characters in the response.

maximum1000000

minimum1

source_type: optional string

The source type of the function.

tags: optional array of string

Metadata tags.

ReturnsExpand Collapse

Tool = object { id, args_json_schema, created_by_id, 14 more }

Representation of a tool, which is a function that can be called by the agent.

id: string

The human-friendly ID of the Tool

args_json_schema: optional map[unknown]

The args JSON schema of the function.

created_by_id: optional string

The id of the user that made this Tool.

default_requires_approval: optional boolean

Default value for whether or not executing this tool requires approval.

description: optional string

The description of the tool.

enable_parallel_execution: optional boolean

If set to True, then this tool will potentially be executed concurrently with other tools. Default False.

json_schema: optional map[unknown]

The JSON schema of the function.

last_updated_by_id: optional string

The id of the user that made this Tool.

metadata_: optional map[unknown]

A dictionary of additional metadata for the tool.

name: optional string

The name of the function.

npm_requirements: optional array of NpmRequirement { name, version }

Optional list of npm packages required by this tool.

name: string

Name of the npm package.

minLength1

version: optional string

Optional version of the package, following semantic versioning.

pip_requirements: optional array of PipRequirement { name, version }

Optional list of pip packages required by this tool.

name: string

Name of the pip package.

minLength1

version: optional string

Optional version of the package, following semantic versioning.

return_char_limit: optional number

The maximum number of characters in the response.

maximum1000000

minimum1

source_code: optional string

The source code of the function.

source_type: optional string

The type of the source code.

tags: optional array of string

Metadata tags.

tool_type: optional ToolType

The type of the tool.

Accepts one of the following:

"custom"

"letta_core"

"letta_memory_core"

"letta_multi_agent_core"

"letta_sleeptime_core"

"letta_voice_sleeptime_core"

"letta_builtin"

"letta_files_core"

"external_langchain"

"external_composio"

"external_mcp"

Upsert Tool

HTTP

• HTTP
• TypeScript
• Python

curl https://api.letta.com/v1/tools/ \
    -X PUT \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $LETTA_API_KEY" \
    -d '{
          "source_code": "source_code"
        }'

200 example

{
  "id": "tool-123e4567-e89b-12d3-a456-426614174000",
  "args_json_schema": {
    "foo": "bar"
  },
  "created_by_id": "created_by_id",
  "default_requires_approval": true,
  "description": "description",
  "enable_parallel_execution": true,
  "json_schema": {
    "foo": "bar"
  },
  "last_updated_by_id": "last_updated_by_id",
  "metadata_": {
    "foo": "bar"
  },
  "name": "name",
  "npm_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "pip_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "return_char_limit": 1,
  "source_code": "source_code",
  "source_type": "source_type",
  "tags": [
    "string"
  ],
  "tool_type": "custom"
}

Returns Examples

200 example

{
  "id": "tool-123e4567-e89b-12d3-a456-426614174000",
  "args_json_schema": {
    "foo": "bar"
  },
  "created_by_id": "created_by_id",
  "default_requires_approval": true,
  "description": "description",
  "enable_parallel_execution": true,
  "json_schema": {
    "foo": "bar"
  },
  "last_updated_by_id": "last_updated_by_id",
  "metadata_": {
    "foo": "bar"
  },
  "name": "name",
  "npm_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "pip_requirements": [
    {
      "name": "x",
      "version": "version"
    }
  ],
  "return_char_limit": 1,
  "source_code": "source_code",
  "source_type": "source_type",
  "tags": [
    "string"
  ],
  "tool_type": "custom"
}