v0.3.0-alpha01 — extensible Tool API (alpha)

First alpha of the extensible tool API. Pre-release — the public API is still far from stable.

Highlights

Tools are now class-based and extensible (breaking)

Tool is an abstract class you can extend for reusable, dependency-injected tools — mirroring how a concrete agent extends ToolLoopAgent — with a new StreamingTool base for Flow-returning tools. Override the executor and only the hooks you need (needsApproval, toModelOutput, onInput*). The tool { } / streamingTool { } / dynamicTool / providerExecutedTool factories keep identical signatures (now backed by internal LambdaTool / LambdaStreamingTool).

class SearchDocsTool(private val repo: DocRepository) :
    Tool<SearchInput, List<SearchResult>, AppContext>(
        name = "searchDocs",
        description = "Search the product documentation",
        inputSerializer = serializer(),
        outputSerializer = serializer(),
    ) {
    override suspend fun ToolExecutionContext<AppContext>.execute(input: SearchInput) =
        repo.search(input.query)
}

Tool input resolved before the approval gate

The loop resolves each tool call's input (decode + a single experimental_repairToolCall attempt) once, before the approval gate — so tool-call repair now reaches subclass tools too, with no double-decode. Approval-gated tools stay gated over their original, cleanly-decoded input.

Telemetry revamp (upstream v7 parity)

A typed Telemetry interface the agent loop feeds automatically (agent / step / model-call / tool-call start+finish, errors, aborts) with a per-invocation TelemetryCall correlation envelope. registerTelemetry(...) / globalTelemetry replace the old *Integration APIs; ToolLoopAgent gains a telemetry parameter.

HMAC-signed tool approvals (AI SDK ref 6.0.202)

ToolLoopAgent gains experimental_toolApprovalSecret: ByteArray? — issued approval requests are signed and replayed approvals are re-validated fail-closed.

Breaking changes

• The public Tool.executor / Tool.needsApproval / Tool.toModelOutput / Tool.onInput* fields are removed (now methods). Construct via the unchanged factories, or extend Tool / StreamingTool; drive directly with executeTool(tool, input, ctx).
• Telemetry *Integration APIs replaced (see above).

Install

implementation("ai.torad:torad-aisdk:0.3.0-alpha01")

Full details in the CHANGELOG.