Agent Runtime Protocol Specification

Document ID: AGENT-009
File Path: docs/04-agent-framework/agent-runtime-protocol.md
Version: 1.0.0
Status: Draft
Owner: AI Platform Team
Last Updated: 2026-06-26

1. Purpose

The Agent Runtime Protocol defines the canonical execution contract between all core subsystems of the Wovyr AI Platform:

Workflow Engine
Agent Runtime
Tool Framework
Memory System
Provider SDK
Policy Engine
Multi-Agent Coordination

It ensures every agent execution is deterministic, observable, secure, and reproducible across distributed environments.

2. Objectives

The protocol shall provide:

Standardized execution lifecycle
Cross-system communication contract
Deterministic state transitions
Streaming execution support
Failure recovery semantics
Distributed execution consistency
Observability hooks
Replay capability

3. Design Principles

Every execution is stateful and traceable.
Every state transition is event-driven.
All subsystems communicate via typed events.
No subsystem directly mutates another subsystem’s state.
Execution is replayable from logs alone.
Failures are explicit states, not exceptions.
Streaming is first-class.

4. High-Level Protocol Flow

Workflow Engine
      │
      ▼
Agent Runtime (Protocol Core)
      │
      ├──────────────┬──────────────┬──────────────┐
      ▼              ▼              ▼              ▼
Policy Engine   Memory System   Tool Framework   Provider SDK
      │              │              │              │
      └──────────────┼──────────────┼──────────────┘
                     ▼
          Multi-Agent Coordination
                     │
                     ▼
             Execution Results

5. Execution Lifecycle

Each agent execution follows a strict lifecycle:

CREATED
   ↓
VALIDATED
   ↓
PLANNED
   ↓
CONTEXT_BUILT
   ↓
POLICY_CHECKED
   ↓
EXECUTING
   ↓
STREAMING (optional)
   ↓
TOOL_INVOKED (optional)
   ↓
COMPLETED
   ↓
PERSISTED
   ↓
ARCHIVED

Failure states:

FAILED
RETRYING
CANCELLED
TIMED_OUT
DENIED

6. Execution Request

executionId:
workflowId:
agentId:
tenantId:
goal:
input:
contextId:
priority:
timeout:
retryPolicy:
metadata:

7. Execution Context Contract

The runtime context is immutable once created:

context:
  workflowState:
  memorySnapshot:
  toolCapabilities:
  policySnapshot:
  providerSelection:
  tokenBudget:
  traceId:

8. Event-Driven Architecture

All communication occurs via events.

Core Events

ExecutionCreated
ExecutionValidated
ExecutionPlanned
ContextBuilt
PolicyEvaluated
ToolInvoked
ProviderCalled
MemoryQueried
AgentDelegated
ExecutionCompleted
ExecutionFailed
ExecutionCancelled

9. Event Structure

eventId:
eventType:
executionId:
workflowId:
timestamp:
source:
payload:
correlationId:
traceId:

Events are immutable and append-only.

10. Streaming Protocol

Streaming uses chunked event delivery.

START
  ↓
CHUNK
  ↓
CHUNK
  ↓
CHUNK
  ↓
FINAL
  ↓
COMPLETE

Each chunk is independently verifiable.

11. Tool Invocation Contract

Tool execution follows a strict request-response protocol:

Agent Runtime
      ↓
Tool Dispatcher
      ↓
Policy Engine Check
      ↓
Sandbox Execution
      ↓
Result Stream
      ↓
Response Aggregation

Tool results are normalized before returning to the agent.

12. Provider Invocation Contract

LLM calls follow:

Context Manager
      ↓
Provider SDK
      ↓
Provider Router
      ↓
Model Execution
      ↓
Response Stream
      ↓
Token Accounting

Provider responses are mapped into a unified format.

13. Memory Interaction Contract

Memory operations are read-heavy and event-tracked:

Retrieve
Store
Update
Embed
Search

All memory access is policy-checked.

14. Policy Enforcement Hook

Before ANY execution step:

Policy Engine Evaluate()

Decision outcomes:

ALLOW → continue
DENY → terminate
CONDITIONAL → require approval
RETRY → re-evaluate later

15. Multi-Agent Delegation Contract

Delegation flow:

Agent A
   ↓
Coordination Manager
   ↓
Agent Registry
   ↓
Agent B Assigned
   ↓
Message Bus
   ↓
Execution Continues

All delegations are trace-linked.

16. State Machine Rules

Rules:

States are strictly ordered
No skipping states
Invalid transitions are rejected
Retry resets EXECUTING state only
Failure states are terminal unless retried

17. Checkpointing Integration

Each execution state can be checkpointed:

Execution State Snapshot:
  - currentState
  - completedSteps
  - memoryDiff
  - toolOutputs
  - providerState

Checkpoint enables full recovery.

18. Distributed Execution Model

Executions may migrate across nodes:

Node A → Node B → Node C

Rules:

Execution ID remains constant
State is synchronized via event log
No duplicate execution allowed
At-most-once tool execution guarantee

19. Retry Semantics

Retry policies:

Immediate retry
Backoff retry
Failover provider retry
Alternate tool retry

Retries preserve execution context.

20. Error Handling Model

Errors are classified:

Type	Description
ValidationError	Invalid input
PolicyDenied	Security violation
ToolFailure	Tool execution error
ProviderFailure	LLM failure
Timeout	Execution exceeded limit
SystemFailure	Infrastructure issue

All errors are evented.

21. Observability Hooks

The protocol exposes:

Traces
Metrics
Logs
Execution DAG
State transitions

OpenTelemetry-compatible tracing is required.

22. Security Requirements

mTLS for all communication
Signed events
Tenant isolation
Secret redaction
Policy enforcement before execution
No raw secret exposure to LLM

23. Rust Interface

pub trait AgentRuntimeProtocol {
    fn execute(request: ExecutionRequest) -> ExecutionHandle;

    fn stream(execution_id: ExecutionId) -> EventStream;

    fn cancel(execution_id: ExecutionId) -> Result<()>;

    fn checkpoint(execution_id: ExecutionId) -> Result<()>;
}

24. Module Organization

engine-runtime-protocol/
├── lifecycle/
├── events/
├── execution/
├── streaming/
├── state-machine/
├── checkpoint/
├── distributed/
├── errors/
├── security/
└── mod.rs

25. Testing Strategy

Unit Tests

State transitions
Event validation
Retry logic
Error classification

Integration Tests

Tool Framework
Memory System
Provider SDK
Policy Engine

Distributed Tests

Multi-node execution
Failover recovery
Event consistency
Checkpoint restoration

26. Non-Functional Requirements

Requirement	Target
State transition latency	< 5 ms
Event emission	< 2 ms
Execution dispatch	< 10 ms
Checkpoint restore	< 200 ms
Availability	99.99%

27. Dependencies

docs/03-workflow-engine/state-machine.md
docs/03-workflow-engine/event-bus.md
docs/03-workflow-engine/distributed-execution.md
docs/04-agent-framework/tool-framework.md
docs/04-agent-framework/policy-engine.md

docs/04-agent-framework/agent-definition.md
docs/04-agent-framework/context-manager.md
docs/04-agent-framework/multi-agent-coordination.md

29. Future Enhancements

Zero-copy execution protocol
WASM-native agent runtime
GPU-accelerated execution paths
Self-healing execution graphs
AI-driven runtime optimization
Cross-cloud execution federation

30. Revision History

Version	Date	Description
1.0.0	2026-06-26	Initial Agent Runtime Protocol Specification