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 states the operation is a read ('Return') with no side effects implied, but does not disclose potential failure modes, error handling, or any behavior beyond the basic call. The phrase 'well-known location' hints at a standard endpoint but doesn't specify what happens if it's unreachable or the format of the response.

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 a single, concise sentence with no redundant information. It front-loads the action and resource immediately, making it efficient for an agent to parse.

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?

For a zero-parameter retrieval tool, the description is reasonably complete. It identifies what is returned and where it's published, but it lacks details about the output structure (e.g., what fields the Card contains) and any error conditions. Since there's no output schema, the description could compensate, but for a standard A2A concept, this might be sufficient for many agents.

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 schema is empty and fully covered. The description adds no parameter information because there are none to explain. Per the baseline rule for 0 params, a score of 4 is appropriate.

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 clearly identifies the action ('Return') and the resource ('the A2A Agent Card'), and mentions 'well-known location' implying a standard retrieval. However, it does not differentiate this from sibling tools like oracle.service_descriptor or oracle.discovery_bundle, which may also return similar metadata. It's clear on its own but lacks explicit sibling differentiation.

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 provides no guidance on when to use this tool versus alternatives. It only states what it does without any context about when it's appropriate (e.g., when you need the agent's identity card vs. discovery bundle). No exclusions or alternative recommendations are mentioned.

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