Flow-first executor: emit one ToolResult.Success per value. The LAST emission is the final result that feeds the model; earlier emissions surface as preliminary tool results. Extend StreamingTool and override StreamingTool.executeStream for the streaming case.

needsApproval

open suspend fun needsApproval(input: TInput, options: ToolPredicateOptions<TContext>): Boolean

Approval gate — return true to pause the loop for host approval. Default: never gates.

onInputAvailable

open suspend fun onInputAvailable(toolCallId: String, input: TInput)

onInputDelta

open suspend fun onInputDelta(streamingId: String, delta: String)

onInputStart

open suspend fun onInputStart(streamingId: String)

toModelOutput

open fun toModelOutput(output: TOutput, options: ToolPredicateOptions<TContext>): ToolResultOutput?

Model-visible summary. Return null to send raw output as-is.