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

Annotations already cover read-only, idempotent, open-world, and non-destructive behavior. The description adds meaningful behavioral context beyond annotations: no API key is required, the descriptor is hash-verifiable, and the fetched data is identical to /.well-known/agent.json. No contradictions 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?

The description is compact, front-loaded with the immediate call directive, and each sentence provides distinct information. There is slight redundancy between listing schema_url/schema_hash earlier and repeating the fetch in the final sentence, 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?

Given the absence of parameters, the presence of an output schema, and annotations covering the safety profile, the description supplies all necessary context for an agent to call the tool correctly: what it returns, where it matches a well-known file, and when to call it. No critical information 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?

The tool takes zero parameters, and the schema already explains that the owner is derived from the authenticated principal. Per the baseline for zero-parameter tools, the description does not need to add more; nothing is missing.

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 resource being fetched: the AgentContractV1 descriptor with version, schema_url, and schema_hash, plus hosted_runtime facts. It is specific and references the well-known /.well-known/agent.json, but it does not explicitly differentiate this tool from nearby siblings like verify_contract or discover_agents, which keeps it from a 5.

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 gives an explicit when-to-use direction: 'call this now' and 'before acting', indicating this is a preliminary step that requires no API key. However, it does not mention when not to use it or direct users to an alternative sibling, so it stops short of full guidance.

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