| Area | Public surface | Runtime guarantee |
|---|---|---|
| Adapters | LocalFunctionToolAdapter, PluginToolAdapter, MockToolAdapter, HttpToolAdapter, MCPToolAdapter |
Provider and transport details stay behind one ToolAdapter contract. |
| Governance | ToolSpec, GovernedToolContractSpec, GovernedToolRunner |
Input/output validation, permissions, policy, approval, audit, timeout, retry, and cancellation run on one path. |
| Invocation reliability | ToolInvocationStore, ToolApprovalStore, recovery and reconciliation ports |
Idempotency is scope-aware; approval is revision-checked; unknown side-effect commit state becomes conflict. |
| Output and observations | Artifact and observation ports | Oversized output can become an artifact; observation records retain hashes and provenance. |
| Result reuse | bounded memory or Redis ToolResultCache and versioned validity records |
Reuse is key-bound, runtime-validated, revision/policy/scope-aware, and restricted to safe side-effect levels. |
| MCP transport | stdio and Streamable HTTP connection sessions | Initialization, pagination, cancellation, health, reconnect, and cleanup stay in the MCP boundary. |
| MCP catalog | Capability catalog, trust and drift records, schema cache | Capability revisions are canonicalized; drift can require approval or quarantine. |
| Stable Runs | Tool contract snapshot store | Active and replayed Runs resolve the immutable contract snapshot selected at Run start. |
| Domain and FSM | ToolProfileSpec and workflow state bindings |
Only selected profile/state Tools are loaded; state denies take precedence over all allow sources. |
| Server API | Tool execution, Invocation, Approval, MCP server/capability/drift routes | HTTP commands delegate to the governed runner and event-first runtime. |
| Observability | Tool/MCP events, telemetry, audit payloads | Events carry governed hashes, references, attempts, decisions, and redacted values according to audit policy. |
Contract exports include TypeScript types, Zod validators, JSON Schema, examples, and definitions for governed Tools, Invocations, approvals, snapshots, events, MCP integrations, connections, capabilities, drift records, and normalized errors.