Tool engines

A tool set file points at a remote gRPC service and lists the methods the model may call. SGPT resolves the service’s schema over reflection and turns each method into a tool — the same derivation used for the built-ins: comments become descriptions, request messages become JSON schemas, NO_SIDE_EFFECTS methods auto-execute.

A tool set file

.sgpt/jira.toolset:

{
  "engine_service": "onikisu-staging",
  "tool_sets": [
    {
      "service_full_name": "gateway.integration.jira.v1.JiraGateway",
      "method_names": [
        "GetIssue", "ListIssues", "CreateIssue", "UpdateIssue",
        "ListSprints", "StartSprint", "CloseSprint"
      ],
      "schema_configuration": {
        "with_max_depth": 8,
        "with_response_read_mask": true,
        "with_response_schema_max_depth": 2
      }
    }
  ]
}

• engine_service names a grpc_clients entry from the configuration — the engine that serves the AiEngine API and proxies calls.
• Each entry in tool_sets is a CreateServiceToolSetRequest: a service, the methods to expose, and schema tuning (depth caps keep argument schemas small enough for the model).

The file’s selector is its tool name: --tool jira, --tool //:jira, @tool("@onikisu//:jira").

Lazy by design

Engines are listed at startup (so pickers and completion know them) but dialed only when first enabled — on the command line, by a role, or from the picker. Schema resolution and tool set creation happen once per engine per process and are cached.

Discovery

Large services can be exposed as discoverable: instead of advertising every method up front, the engine advertises a discover tool. The system prompt then teaches the protocol — discover before calling, discover everything you need in one turn — and the tool sets are attached when the model asks. Discovery calls are auto-resolved at review time; nothing runs.

Rendering

RPC calls render as Service/Method with the request as JSON; results render as JSON with the response read mask applied. Big responses are collapsible in the timeline (alt+z).