Get agent card

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

The readOnlyHint and openWorldHint annotations already establish that this is a non-mutating read operation. The description adds context by identifying the fixed target agent and the contents of the returned card, but it does not go further into behaviors like error conditions or availability of the document.

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?

A single, front-loaded sentence that names the action and the resource before listing contents. Every word earns its place, with no redundancy or filler.

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?

This is a simple, parameterless read tool with annotations clarifying safety and open-world behavior. The description fully conveys what the returned card contains, so an agent has enough context to call it correctly without an output schema.

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?

The tool has zero parameters, so the input schema contributes nothing. The description compensates by clarifying what the returned artifact is, though there is no parameter information to add.

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 uses a specific verb ('Fetch') and resource ('the A2A agent card'), and enumerates the contents (name, version, capabilities, skills, I/O modes, security schemes). This clearly distinguishes it from sibling tools like ask_agent or reset_conversation, which address different actions.

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?

The description implies when to use the tool: whenever an agent needs the A2A agent's metadata or capabilities. However, it does not explicitly state when not to use it or name alternatives such as ask_agent for interactive queries, leaving some routing decisions to inference.

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