Agent Signal

Agent Signal

Use this skill to implement event-driven background work for agents without coupling the work to the foreground chat request.

Agent Signal has one consistent runtime shape:

source event -> signal interpretation -> action execution -> built-in result signals

Durable self-iteration work has one extra completion branch:

memory/skill action -> execAgent enqueue -> agent.execution.completed -> selfIteration receipt projection

Start Here

1. Read references/architecture.md to map the package boundary, runtime queue, scope model, and async workflow handoff.
2. Read references/handlers.md before writing any new policy, source handler, signal handler, or action handler.
3. Read references/observability.md when you need tracing, metrics, debugging, or workflow snapshot visibility.

Use The Right Entry Point

• Use emitAgentSignalSourceEvent(...) when a server-owned producer should execute the pipeline immediately.
• Use executeAgentSignalSourceEvent(...) when a worker or controlled backend path already owns execution timing and may inject a runtime guard backend.
• Use enqueueAgentSignalSourceEvent(...) when the caller should return quickly and let Upstash Workflow process the event out-of-band.
• Use emitAgentSignalSourceEventWithStore(...) for isolated tests or evals that should avoid ambient Redis state.

Read:

• apps/server/src/services/agentSignal/index.ts
• apps/server/src/workflows/agentSignal/index.ts
• apps/server/src/workflows/agentSignal/run.ts

Core Model

• source: A normalized fact that happened. Sources come from producers such as runtime lifecycle events, user messages, or bot ingress.
• signal: A semantic interpretation derived from one source or from another signal. Signals express meaning, routing, or policy state.
• action: A concrete side effect planned from one signal. Actions do the work.
• policy: An installable middleware bundle that registers source, signal, and action handlers.
• procedure: Not a distinct runtime node. Treat "procedure" as the end-to-end flow for one use case: ingress source, matching handlers, planned actions, execution result, and observability.

Keep the boundaries strict:

• Add a new source when the outside world produced a new event.
• Add a new signal when the system needs a reusable semantic interpretation.
• Add a new action when the runtime needs a concrete side effect.
• Add or update a policy when you are wiring those pieces together.

Implementation Workflow

1. Decide whether the use case is synchronous or quiet background work.
2. Define or reuse a source type in packages/agent-signal/src/source/sourceTypes.ts.
3. Define or reuse signal and action types in apps/server/src/services/agentSignal/policies/types.ts.
4. Implement handlers with defineSourceHandler, defineSignalHandler, or defineActionHandler.
5. Add source normalization or hydration under apps/server/src/services/agentSignal/sources/** when the producer payload needs shaping.
6. Bundle handlers with defineAgentSignalHandlers(...).
7. Register the policy in apps/server/src/services/agentSignal/policies/index.ts and pass it into the runtime factory if needed.
8. Add or update ingress code that emits or enqueues the source event.
9. For async self-iteration writes, stamp an Agent Signal operation marker and project user-visible receipts from the completion path.
10. Add observability and tests before considering the flow complete.

Default Reading Set

• Shared semantic core: packages/agent-signal/src/index.ts packages/agent-signal/src/base/builders.ts packages/agent-signal/src/base/types.ts packages/agent-signal/src/source/sourceTypes.ts packages/agent-signal/src/source/sourceEvent.ts
• Server-owned runtime and middleware: apps/server/src/services/agentSignal/runtime/AgentSignalRuntime.ts apps/server/src/services/agentSignal/runtime/AgentSignalScheduler.ts apps/server/src/services/agentSignal/runtime/middleware.ts apps/server/src/services/agentSignal/runtime/context.ts
• Existing policy example: apps/server/src/services/agentSignal/policies/analyzeIntent/index.ts apps/server/src/services/agentSignal/policies/analyzeIntent/feedbackSatisfaction.ts apps/server/src/services/agentSignal/policies/analyzeIntent/feedbackDomain.ts apps/server/src/services/agentSignal/policies/analyzeIntent/feedbackAction.ts apps/server/src/services/agentSignal/policies/analyzeIntent/actions/userMemory.ts apps/server/src/services/agentSignal/policies/analyzeIntent/actions/skillManagement.ts apps/server/src/services/agentSignal/policies/analyzeIntent/completionSkillSynthesis.ts apps/server/src/services/agentSignal/policies/completionPolicy.ts apps/server/src/services/agentSignal/services/selfIteration/completion/buildSelfIterationReceipts.ts apps/server/src/services/agentSignal/services/selfIteration/completion/selfIterationCompletionHandler.ts
• Observability: apps/server/src/services/agentSignal/observability/projector.ts apps/server/src/services/agentSignal/observability/traceEvents.ts packages/observability-otel/src/modules/agent-signal/index.ts

Implementation Rules

• Reuse existing source, signal, and action types before adding new ones.
• Keep source handlers focused on interpretation and fan-out, not heavy side effects.
• Keep action handlers responsible for side effects, idempotency, and executor-style result reporting. For memory/skill self-iteration actions, the side effect is enqueueing execAgent; the durable write and receipt projection happen after completion.
• Use stable ids and idempotency keys when the same source can arrive more than once.
• Preserve scope discipline. The runtime uses scopeKey to serialize related background work.
• Prefer the dedicated shared package types and builders from @lobechat/agent-signal for normalized nodes and result contracts.
• Do not project memory or skill receipts from the enqueue action. Use agent.execution.completed + selfIteration finalState via createSelfIterationCompletionHandler(...).
• Add focused tests near the touched runtime, policy, or store module. Existing tests under apps/server/src/services/agentSignal/**/__test__ and **/__tests__ are the reference pattern.

References

• Architecture and boundaries: references/architecture.md
• Writing handlers and policies: references/handlers.md
• Observability, metrics, and debugging: references/observability.md