Orchestration Patterns and Handoff Artifacts for Multi‑Agent Systems

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Effective multi‑agent workflows require two concrete deliverables in the spec: (1) clear role definitions for each agent involved, and (2) well‑typed handoff artifacts (the documents/messages agents exchange). Together these make orchestration deterministic, testable, and easy to review.

Agent roles: how to name and describe responsibilities

Give every role a short canonical name and a 1–2 sentence description that answers: purpose, inputs it expects, outputs it must produce, and authority (what it may change or approve). Include:

Responsibilities: bullet list of concrete actions (e.g., “triage incoming request; attach diagnostic log; decide pass/fail or route to specialist”).

Entry criteria: what constitutes a valid input (schemas, minimum fields, required artifacts).

Exit criteria / Acceptance: exact conditions and tests that mark the role’s task complete.

Failure policy: how the role signals unresolved work (retries, escalate to human, create incident ticket).

Permissions & tools: APIs, credentials, or tools the agent can call; any rate limits or side‑effect constraints.

Common orchestration patterns (when to use each)

Sequential pipeline: deterministic, linear handoffs (A → B → C). Use when task steps are known and each step requires full context from the prior step. Pros: simple to test and reason about. Cons: slower; single‑point latency.

Orchestrator / manager (magentic) pattern: a manager agent plans, invokes specialists, evaluates results, and replans. Best for open‑ended tasks where the step sequence is unknown ahead of time. Pros: flexible and expressive. Cons: higher cost, more complex debugging.

Handoff (triage) pattern: a first‑contact agent routes ownership to a specialist and then exits. Use when initial classification determines the specialist. Pros: clean ownership transfer; simple logs. Cons: potential for bouncing unless routing rules are strict.

Concurrent / fan‑out & synthesize: run independent assessments in parallel and synthesize results (fan‑out → fan‑in). Use when tasks are decoupled and benefits from speed or independent verification. Pros: fast; supports independent validators. Cons: requires an aggregator and careful merging rules.

Event‑driven / blackboard: agents post facts to a shared event feed or store; other agents react. Use for highly decoupled systems or when agents can opportunistically contribute. Pros: scalable and extensible. Cons: eventual consistency; requires strong schemas and idempotency.

Handoff artifacts: formats, required fields, and validation

Define a small set of versioned artifact types (JSON or markdown + metadata) with explicit schemas. For each artifact type include:

Schema name & version: e.g., task_packet.v1.2.json.

Required fields: id, source_role, created_at (ISO8601), context_snapshot (pointer or small embedded context), payload (typed object), acceptance_tests (list of test commands or validation checks), provenance (agent id + spec version).

Optional fields: attachments (URLs), hints (priority, deadline), trace (references to upstream artifact ids).

Validation rules: supply JSON Schema or equivalent; define syntactic + semantic checks agents must run before accepting an artifact. Include example valid and invalid artifacts.

Handoff semantics and guarantees

Specify the expected delivery and visibility semantics explicitly:

Ownership transfer: whether the receiving agent becomes sole owner (true handoff) or the originator retains oversight (delegation).

Idempotency: how to detect and ignore duplicate artifacts (use stable ids and sequence numbers).

Atomicity & side effects: whether a handoff implies committing side effects (e.g., writing to DB, calling external API) and how agents confirm success or compensate on failure.

Operational artifacts to include in the spec

– Role catalogue: table of all roles, short descriptions, entry/exit criteria.

– Artifact registry: all artifact schemas with examples and validators.

– Orchestration diagrams: simple flow diagrams per pattern showing message names, agents, and storage points.

– Acceptance tests: end‑to‑end scenarios that exercise the orchestration (happy path + failure modes) and exact commands/scripts to run them.

Testing and observability

Require each handoff artifact to carry trace ids to enable end‑to‑end replay and observability. Define metrics to collect: handoff latency, handoff failure rate, bounce rate (percent of artifacts re‑routed), and percent of tasks requiring human escalation. Include a minimal log format for trace events (timestamp, agent, artifact_id, action, result).

Following these conventions turns the checklist item “Orchestration: agent roles + handoff artifacts” into a concrete, testable section of your spec that supports parallel work, reliable handoffs, and straightforward review.

Sources

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