XIV · Anti-PatternsAnti-pattern✕

Role-Typed Subagents

also known as Predefined-Role Multi-Agent, Manager-Coder-Designer Layout, Fixed-Role Crew

Anti-pattern: pre-allocate roles (manager, coder, designer, researcher) across a fixed set of typed sub-agents and route tasks to them by role label.

Context

A team is designing a multi-agent system and, before seeing real workloads, decides on a fixed set of roles — typically manager, researcher, coder, designer, reviewer — and gives each role its own narrow system prompt and restricted tool palette. The orchestrator routes each task to a sub-agent by matching the task to a role label. The architecture diagram looks like clean separation of concerns, and each specialist agent is cheaper per call than a general-purpose one.

Problem

Real workloads do not partition cleanly into the roles the architect imagined in advance. Tasks that fall between two roles get squeezed into whichever label is closest, and the chosen specialist underperforms because its tool palette is missing what the task actually needs. Adding a new role means changing the architecture rather than parameters, and capability-equal parallelism — running many fully capable, identical sub-agents in parallel on the same subtask — is structurally impossible because no sub-agent has the full tool set.

Forces

  • Role labels make the architecture diagrammable and look like sound separation of concerns.
  • Cheaper per-call specialised prompts can outperform a single generalist on narrow tasks.
  • Real workloads do not partition cleanly into the roles named in advance.
  • Capability-equal fan-out (clone-fan-out-research) requires general-purpose sub-agents, which a typed role table forbids.

Example

A team builds a multi-agent product with manager, researcher, coder, and designer sub-agents, each with its own tightly scoped tool palette. A new task type — multilingual marketing copy with light data analysis — fits none of the roles, so it is forced into the researcher role and underperforms. The team rewrites the system: one general-purpose sub-agent shape with the full tool palette, and a per-call system-prompt overlay when specialisation pays. The marketing task now succeeds; a later wide-research task fans out twenty capability-equal instances against the same prompt, which the typed crew could not have done.

Diagram

Solution

Therefore:

Don't bake role types into the architecture. Use one general-purpose sub-agent shape with the full tool palette and let the orchestrator route by task content, not role label. When specialisation pays, scope it per-call (system-prompt overlay, tool subset for this task) rather than per-agent-type. For wide tasks, prefer capability-equal fan-out over typed crews. See clone-fan-out-research, role-assignment (the valid form: per-call persona, not per-agent type), supervisor.

What this pattern forbids. By definition, this anti-pattern imposes no useful constraint; the constraint it adds — fixed role membership — forbids capability-equal parallelism and tasks outside the anticipated role table.

And the patterns that stand alongside it, or against it —

  • alternative-toClone Fan-Out Research·— Spawn 100 or more identical, full-capability agent instances in parallel — each a complete general agent rather than a role-specialised worker — and aggregate their independent outputs into a single answer.
  • alternative-toRole Assignment★★— Assign each agent a named role (researcher, writer, critic, planner) with a role-specific prompt, tool palette, and acceptance criteria.
  • alternative-toSupervisor★★— Place a coordinating agent above a set of specialised agents and route work to them.
  • complementsOrchestrator-Workers★★— An orchestrator dynamically breaks a task into subtasks at runtime and delegates each to a worker LLM, then synthesises results.
  • alternative-toPersonality Variant Overlay·— Let one agent speak in several named voices that overlay the base identity rather than replacing it, so the agent can shift register without losing identity continuity or splitting into separate personas.

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References

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