tools.yaml

tools.yaml declares custom tools. Every tool belongs to one of three implementation classes; the platform owns schema serving, validation, and routing.

Tool classes

`handler_type`	Served by	Notes
`platform_builtin`	the runtime	A fixed set shipped with the platform.
`mcp`	an MCP server	Registered in `policy.yaml`; namespaced by prefix.
`http`	the HTTP executor	Requires an `http` block. The default class.

Custom tool schema

string

required

What the tool does.

string

platform_builtin, mcp, or http. Defaults to http.

object

Input fields (alias: parameters).

object

Output fields (alias: returns).

object

For HTTP tools: method, url, and optional headers, body, timeout_seconds, retry.

object

For HTTP tools: maps response fields to output.

list

For HTTP tools: credential keys resolved at call time.

The fields endpoint and type are not accepted; use http.url and handler_type.

Example

tools.yaml

knowledge_base_search:
  description: Search the support knowledge base.
  handler_type: http
  input_schema:
    query: text
    max_results: integer
  http:
    method: POST
    url: "https://kb.internal/search"

workflow_registered and api_call are deprecated handler types. They still load (workflow_registered normalizes to http when an http block is present), but new tools should use handler_type: http or an MCP server.

See Tools for the authoring guide and the MCP client model.

Contract reference

Language reference

Operations reference

Tool classes

Custom tool schema

Example

​Tool classes

​Custom tool schema

​Example

Tool classes

Custom tool schema

Example