ToolCallStepDefinition

Tool-call step — dispatches a single named V4 tool. Stuart 2026-05-19: the read-shape stored in ``workstreams.workstream.steps`` for V4 workstream templates uses ``type='tool_call'`` with ``tool_name``/``tool_params`` directly on the step. The write-side schema previously had no such variant, which caused every PATCH that included an existing tool_call step to 422 (`StepEditOverride` localStorage workaround in `apps/workstream-studio/src/lib/stepEditOverrides.ts`). This class closes that round-trip gap. Fields are intentionally permissive: ``tool_params`` is the same free-form ``dict`` the cycle launcher already passes through into ``task.step_definition``. The V4 executor reads ``tool_name`` + ``tool_params`` directly off the step blob.

Field	Type	Description
`id`required	`string`	—
`name`required	`string`	—
`type`	`string`	—
`description`	`string \| null`	—
`depends_on`	`string \| object[]`	—
`stage`	`string \| null`	—
`timeout`	`string \| null`	—
`retry_policy`	`RetryPolicy \| null`	—
`error_handler`	`StepErrorHandler \| null`	—
`impact_level`	`"low" \| "medium" \| "high" \| "critical"`	Impact classification for steps. `lowmediumhighcritical`
`run_mode`	`"propose" \| "auto_run"`	Execution mode for steps. `proposeauto_run`
`requires_approval`	`boolean`	—
`metadata`	`object \| null`	—
`examples`	`StepExample[] \| null`	Attached example files for this step. Each entry pairs a platform.file_uploads.file_id with a role + tags + notes so the runtime can shape its instruction. Bounded at 20 to keep a reasonable upper limit on the prompt preamble.
`tags`	`string[] \| null`	Categorical labels on the step itself (e.g. 'pdf-read', 'coutts', 'fy25'). Free-form; recommended tag set is documented per workstream surface.
`tool_name`required	`string`	V4 tool identifier (e.g. 'read_pdf_document', 'generate_pdf').
`tool_params`	`object`	Free-form parameter bag forwarded to the V4 tool. May contain Jinja2 placeholders like '{{ inputs.* }}'. show nested Empty object.
`expected_outputs`	`object[] \| null`	Optional output schema hints (name + type per entry).
`instruction`	`string \| null`	Optional natural-language instruction the runtime can use to shape the tool dispatch (e.g. prompt preamble for LLM-style tools).
`inputs`	`object \| null`	Input mappings — same Jinja2 surface as TaskStep.