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What it does

The Call Agent tool allows your agents to communicate with and delegate tasks to other agents on the Aster platform. Perfect for creating agent workflows, specialized task delegation, and building complex multi-agent systems.

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Key features

  • Call any agent on your Aster platform
  • Continue conversations across multiple interactions
  • Maintain conversation threads for context
  • Access to called agent’s capabilities and knowledge
  • Seamless agent-to-agent communication

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Parameters

ParameterTypeRequiredDescription
messagestringYesThe message to send to the target agent
agentIdstringYesThe ID of the agent to call
respondToThreadIdstringNoID of existing thread to continue (creates new thread if not provided)

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Common use cases

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Specialized task delegation

message: "Analyze this sales data and create a summary report with key insights"
agentId: "data-analyst-agent-123"

Delegate data analysis to a specialized analytics agent.

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Multi-step workflows

message: "Generate a marketing email for our new product launch"
agentId: "marketing-agent-456"
respondToThreadId: "thread-789"

Continue a conversation thread for complex workflows.

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Expert consultation

message: "Review this code for security vulnerabilities and best practices"
agentId: "security-expert-agent-789"

Get expert review from specialized agents.

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Content creation pipeline

message: "Create a blog post outline about AI trends in 2024"
agentId: "content-writer-agent-101"

Start a content creation workflow with writing specialists.

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Quality assurance

message: "Review and fact-check this research report before publication"
agentId: "qa-agent-202"
respondToThreadId: "research-thread-303"

Add quality control steps to your workflows.

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Customer support escalation

message: "This customer has a complex technical issue that needs expert attention"
agentId: "technical-support-agent-404"

Escalate complex issues to specialized support agents.

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Agent collaboration patterns

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Sequential workflow

  1. Agent A calls Agent B for initial analysis
  2. Agent B returns results to Agent A
  3. Agent A calls Agent C for final processing
  4. Agent C delivers final output

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Parallel processing

  • Call multiple specialized agents simultaneously
  • Combine their outputs for comprehensive results
  • Useful for multi-perspective analysis

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Iterative refinement

  • Use respondToThreadId to continue conversations
  • Refine outputs through multiple interactions
  • Build complex solutions step by step

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Finding Agent IDs

Agent IDs can be found in:

  • The Aster platform agent directory
  • Agent configuration pages
  • Your organization’s agent list
  • Previous call_agent tool responses

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What you get back

  • Agent Response: The called agent’s complete response
  • Thread ID: Unique identifier for the conversation thread
  • Agent Info: Details about the called agent
  • Conversation Context: Full context of the interaction

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Best practices

  • Use clear, specific messages when calling agents
  • Include relevant context and background information
  • Use thread IDs to maintain conversation continuity
  • Choose the right agent for each specific task
  • Monitor agent interactions for workflow optimization
  • Set up proper agent permissions and access controls

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Troubleshooting

“Agent not found”

  • Verify the agent ID is correct
  • Check that the agent exists and is active
  • Ensure you have permission to call the agent

“Access denied”

  • Verify your agent has permission to call the target agent
  • Check that the target agent allows incoming calls
  • Ensure proper authentication and authorization

“Thread not found”

  • Verify the thread ID is correct and still active
  • Check that you have access to the conversation thread
  • Ensure the thread hasn’t expired or been deleted

“Agent unavailable”

  • The target agent might be temporarily unavailable
  • Check the agent’s status and availability
  • Try again later or use an alternative agent