a2a-mcp-bridge

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get_a2a_task

Retrieve the status and output of a previously started A2A task by task_id, useful after send_a2a_message timeout or error.

Instructions

Fetch the current state and result of a previously started A2A task.

Use this when send_a2a_message timed out or errored after the task had already started: the task keeps running server-side, and this retrieves its status and any output by the task_id from the error message or the [a2a ...] response footer.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "task_id": "<task_id>"
    },
    "name": "get_a2a_task"
  }
}

Input Schema

Name	Required	Description	Default
`task_id`	Yes
`agent_url`	No		http://localhost:8001

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 9, 2026

TDQS

A4.3/5.0

Behavior4/5

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

No annotations are provided, so the description carries the full burden. It discloses that the tool retrieves status and output, and that the task continues running server-side. It does not explicitly state it is read-only, but that is implied. The description provides useful context for polling behavior but lacks explicit mention of rate limits or authentication.

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

Conciseness5/5

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

Two sentences with no wasted words. The first sentence states the purpose, the second provides usage guidance. Information is front-loaded and easy to parse.

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

Completeness4/5

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

For a simple fetch tool with two parameters (one required) and an output schema, the description covers the key use case (polling after send_a2a_message failure) and explains how to obtain the required task_id. It is missing agent_url explanation, but given its default and typical usage (same as the original message), the overall completeness is high.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate. It explains the task_id parameter indirectly (derived from error messages or response footer), but does not mention the agent_url parameter at all, which has a default but may need to be overridden. The explanation is insufficient for both parameters.

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

Purpose5/5

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

The description starts with a clear verb+resource: 'Fetch the current state and result of a previously started A2A task.' This distinguishes it from sibling tools like send_a2a_message (which starts tasks) and get_agent_card (which retrieves agent information).

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

Usage Guidelines5/5

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

Explicitly states when to use: 'Use this when send_a2a_message timed out or errored after the task had already started.' It provides context that the task runs server-side and explains how to obtain the task_id from error messages or the response footer.

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

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