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Multi-agent patterns

Several model roles with separate context, tools, and budgets, coordinated by code.

What it is and why it exists

What

A multi-agent system splits work across model calls that each have their own instructions, tools, and context. Coordination is done by an orchestrator: fan-out to workers, independent judges, or handoffs between specialists.

Why

One context window cannot hold everything, and one role cannot check itself. Separate roles give isolation of context and independence of judgment. They also multiply cost and failure modes, so each split needs a measured reason.

How it works

Where it sits in the build order

Needs first

  • Harness engineeringA sub-agent is a harness loop run as a node. You need one working loop before you can run several.Build out of order Stub it with: Two sequential model calls with different system prompts.
  • SkillsRoles are defined by scoped instructions. Skills are the mechanism for scoping them.Build out of order Stub it with: Hard-coded role prompts.
  • EvaluationEvery added agent adds cost and latency. Only an eval can show that a split improved results.Build out of order Stub it with: Manual comparison on five questions. Enough to learn the pattern, not enough to justify it.

Unlocks

Nothing depends on this. It is an end point of the map.

In the reference build

PathRole
apps/agent-server/graph.pyThe executor that runs concurrent nodes.
apps/agent-server/nightly/claim_verify.pyTwo-vote judging.
apps/agent-server/skills/spending-orchestration.mdInstructions for decomposing a multi-part data question.
ROLE-DIMENSION-ARCHITECTURE-v2.mdDesign for specialist roles by question dimension.

The same idea on other platforms

PlatformHow this module maps
DatabricksMulti-agent supervisors are available as a managed pattern, and LangGraph or the OpenAI Agents SDK run inside a deployed agent. Each sub-agent can be its own serving endpoint or a function.
IBM watsonxOrchestrate agents list collaborators and route work among them. This is the platform's core pattern.
CodexSubagents run tasks in separate contexts. The Agents SDK supports handoffs between agents.
CursorSubagents and background agents run tasks in parallel with their own context.
Claude Code / Agent SDKSubagents have their own context window and tool set, defined in files. The SDK can spawn them from code.
Another machineThe wave executor is plain Python. Sub-agents are functions.

Explain it back

Answer aloud first. Then open the answer and compare.

Give one good reason and one bad reason to add a second agent.
A strong answerGood: you need an independent check, or a sub-task's context would crowd out the main one. Bad: the architecture diagram looks more capable. Without an eval showing a gain, it is only more cost.
Why two votes for claim verification?
A strong answerA single judge's error would remove true claims. Requiring both to fail trades some missed bad claims for far fewer wrongly removed good ones.

From the live build

Recent changes and files the sync job filed under this module.

Ask the tutor about this module