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

Annotations already declare readOnlyHint=true and openWorldHint=false. The description adds valuable context beyond those annotations: free/no-account access, the self-registration mechanism, and the returned fields (card URL, operator, verification grade, protocol version, transport). No contradiction with annotations.

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?

Three sentences with key access facts front-loaded. The final sentence uses a metaphor ('door an unattended agent can walk through unaided') that is slightly ornamental but still conveys meaningful differentiation about accessibility.

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 simple read-only listing tool with no output schema, the description identifies the returned fields and access requirements, while the schema handles pagination parameters. It could mention result ordering or total counts, but nothing critical for correct invocation is missing.

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 description coverage is 100%, so all three parameters (page, limit, context) are fully documented in the schema. The description adds no additional parameter syntax or behavioral details. Per the rubric, this baseline is 3 when the schema already provides full coverage.

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?

Identifies the specific resource as the A2A agent registry and explains it contains agents that self-registered by serving an agent card and calling register_agent. This distinguishes it from register_agent, but the verb 'find' is only implied by the tool name, not stated in the description.

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?

States that the registry is FREE and needs no account, and that an unattended agent can use it unaided while others require a person or voucher. This gives useful context, but it does not explicitly say when to choose this over sibling tools such as find_agent_readiness or get_agent_readiness.

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