Subagent invocation and context passing

• The Task tool spawns subagents; the coordinator's allowedTools must include Task.
• Subagents do not inherit parent context or share memory between invocations.
• An AgentDefinition sets a subagent type's description, system prompt, and tool restrictions.
• Fork-based session management branches a shared analysis into independent explorations.
• Multiple Task calls in one coordinator response run in parallel; calls across turns run one after another.
• Prompts that state goals and quality criteria let subagents adapt; rigid step lists break on unexpected input.

• Include complete findings from earlier agents directly in the next agent's prompt.
• Pass context as structured data that separates content from metadata (source URL, document name, page number) to preserve attribution.
• Launch parallel subagents by emitting several Task calls in a single response.
• Write coordinator prompts around research goals and quality criteria rather than procedures.

• "The synthesis agent can see what the search agent found." It sees only what the coordinator passes in.
• "A summary of findings is enough." Compressed handoffs lose detail and attribution.
• "Task calls on successive turns still run concurrently." They run sequentially.

Coordinators missing Task in allowedTools, free-text handoffs that drop sources, and step-by-step subagent prompts.

• 1.2Coordinator-subagent orchestration
• 1.7Session state, resumption and forking
• 5.6Provenance and uncertainty