send_a2a_message

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description fully discloses behavior: emits progress notifications, may time out but task continues server-side, response format includes an [a2a ...] line. It clarifies that omitting ids starts a fresh task, and describes how to handle timeouts.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise (approximately 9 lines) and well-structured: purpose first, then response continuation, then timeout handling. Every sentence adds value, no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (asynchronous task-based communication, with progress notifications and timeout recovery) and the presence of an output schema (though not shown), the description covers all necessary context: usage, continuation, error handling, and ties to sibling tools. It is complete for an agent to use correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema has 0% description coverage; the description adds meaning to all 4 parameters: message as content, task_id/context_id for conversation continuity, and agent_url as default endpoint. It explains how omitting ids vs. providing them changes behavior.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description starts with a clear verb-resource pair: 'Send a message to an A2A agent and return its final text response.' It distinguishes from siblings get_a2a_task (retrieve results) and get_agent_card (get metadata) by focusing on initiating or continuing a conversation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit guidance: explains the response format with task_id/context_id, instructs to pass those back to continue the conversation, and advises to tune A2A_TIMEOUT_SECONDS for long-running tasks instead of treating delays as hangs. Also mentions using get_a2a_task if a timeout occurs, linking to the sibling tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.