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

Annotations already declare read-only, idempotent, non-destructive, and open-world. The description adds meaningful context beyond that: no API key is required, the response is identical to a well-known endpoint, and the content is hash-verifiable, which helps the agent trust 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 three sentences and front-loads the most critical fact (no API key needed). Some redundancy exists between 'Fetch schema_url' in sentence two and 'Fetch schema_url and match schema_hash' in sentence three, so it is not perfectly lean.

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 parameterless, read-only tool with an output schema, the description covers the action, the response contents, and the validation workflow. Nothing needed to call correctly is missing; the output schema handles return-value documentation.

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 takes zero parameters, and the schema description already states the owner is derived from the authenticated principal. With no parameters to explain, the description need not add parameter-level detail, and the baseline 4 applies.

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 states the tool fetches a hash-verifiable AgentContractV1 descriptor and hosted_runtime facts, with specific fields and an equivalence to /.well-known/agent.json. It identifies a concrete resource and verb, but does not explicitly differentiate from the sibling verify_contract.

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?

It instructs the agent to call now without an API key and to validate the contract before acting, providing a clear action trigger. However, it gives no comparison with verify_contract or any other sibling, so the when-to-use vs alternatives guidance is implied rather than explicit.

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