Building Agents
MDX
Multi-Agent Systems Explained
When specialized agents help, how they coordinate, and why more agents do not automatically mean better results.
Editorial review: clarity, operational relevance, safety boundaries, and source quality.
Specialization can simplify prompts
Separate agents can own distinct roles such as research, drafting, verification, or coordination. Each receives only the tools and context required for its part of the job.
Specialization is useful when roles need different tools, permissions, context, or evaluation criteria—not merely different personas. A verifier that cannot write data creates a real control boundary. Two agents with identical access exchanging prose usually add cost without adding dependable capability.
Coordination creates overhead
Every handoff adds latency, cost, and another opportunity to lose information. A single agent with a clear workflow is usually the better starting point.
Coordination cost grows through serial calls, duplicated context, ambiguous ownership, and inconsistent assumptions. Compare against one agent with explicit phases before adding workers. Parallelism helps only when tasks are genuinely independent and their outputs can be merged using a clear contract.
Use explicit contracts
Define what each agent receives, produces, and may change. Shared state should be structured and observable rather than hidden in a long conversation among agents.
Use typed handoffs that include objective, inputs, constraints, artifacts, evidence, status, and unresolved questions. Give one coordinator responsibility for the final state, and prevent agents from silently overwriting shared facts. Trace each contribution under one task identifier so failures remain reconstructable.
Practical example
Research, draft, and verify
A research worker can access external sources but cannot publish. It returns claims with evidence IDs. A drafting worker receives only those claims and a style brief. A verifier checks every important sentence against the evidence and returns pass or specific defects. The coordinator alone decides whether to revise or deliver. The separation creates permission and evaluation boundaries, not theatrical role-play.
Field checklist
Apply it in practice
- Justify each agent with a distinct capability or control boundary.
- Benchmark against a simpler single-agent design.
- Use typed, persisted handoff contracts.
- Assign one owner for final task state.
Decision framework
Questions to answer before you build
Multiple agents are justified by real specialization, permission separation, or parallel work. Role-play alone adds latency and failure points without creating a useful boundary.
Why is another agent necessary?
Require a distinct tool set, context boundary, evaluation target, or permission level. Otherwise prefer one agent with explicit phases.
Can work run independently?
Parallelize only tasks that do not depend on each other's intermediate conclusions and can be merged with a clear contract.
Who owns final state?
Give one coordinator authority over completion and persist typed artifacts so workers cannot silently overwrite shared facts.
Common failure signals
Watch for these warning signs
- Splitting one sequential task into conversational handoffs between identical agents.
- Duplicating the full context for every worker and multiplying cost.
- Allowing workers to disagree without a defined resolution and evidence policy.
Selected primary references
Continue with the source material
These sources inform the wider editorial perspective for this topic. They are not presented as line-by-line citations for every statement.