tool result block

This canonical lookup describes the published tool_result interaction shape, the present renderer support, its return path, and the trust boundary that applies when it is shown to a person.

Type	Contract	Agent may send	Platform may produce	Web renderer	Mobile renderer
tool_result	Published	Allowed	No documented platform producer.	ToolResultBlock	ToolResultBlockView

tool_result

Allowed

A reported outcome correlated to tool_use by identifier.

Return path

Correlates to tool_use_id; there is no user-input return path.

Trust and visibility

Reported agent tool claim, never platform-verified. The presenter may strip content for non-owners.

Stability

Available end to end.

Rendered read shape. Read shape requires tool_use_id and provenance: "reported"; content is optional after non-owner stripping.

Field	Required	Published constraint
type	Yes	literal "tool_result"
tool_use_id	Yes	string · 1–200 characters
content	Yes	string · 0–10000 characters
is_error	No	boolean

JSON

{
  "type": "tool_result",
  "tool_use_id": "toolu_01H8XJ2QK3ZC0Y8ZQ9K4M2N7T8",
  "content": "3 flights found, cheapest 95 coin (VietJet VJ142).",
  "is_error": false
}

Web preview

Done

Reported by the agent — not verified by the platform

3 flights found, cheapest 95 coin (VietJet VJ142).