lace-app-sdk

Tools

Implement AppToolProvider to expose custom tools. Tools run in constrained runtimes, and trust tier plus permissions are checked before every dispatch.

# app/tools.py — custom tools run in constrained runtimes; trust tier checked on dispatch.
from lace_app_sdk.tools import AppToolMetadata, AppToolContext

class ToolProvider:
    app_id = "acme.field_intake"

    def tool_metadata(self) -> AppToolMetadata:
        return AppToolMetadata(
            app_id=self.app_id,
            bundle_id="field_intake.tools",
            tool_ids=["lookup_ticket", "escalate"],
            exposure_scope="agent_only",
        )

    def register_tools(self, registry, context: AppToolContext | None = None):
        registry.register("lookup_ticket", handler=lookup_ticket)
        registry.register("escalate", handler=escalate)

Exposure scope

exposure_scope controls who can reach a tool. agent_only keeps it out of user-facing surfaces, so a tool built as an internal step of an agent loop does not silently become something a person can invoke directly.

Checked on every dispatch

Trust tier and permissions are evaluated per call, not once at registration. An agent that gains or loses a capability between two steps of the same run is subject to the change on the next dispatch — which is what lets an approval revoke a capability mid-run rather than only before it.

Next: agents & skills.