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

The description adds meaningful behavioral context beyond the annotations: no API key is required, the response is hash-verifiable, and the content is identical to /.well-known/agent.json. It also tells the agent how to validate the contract before acting, which is useful operational detail. No contradiction with the read-only, idempotent, non-destructive 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 and front-loaded: the most actionable fact (no API key needed, call now) comes first, followed by precise content details and validation steps. Every sentence earns its place and there is no fluff.

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, read-only fetch tool with an output schema present, the description is complete. It explains what is fetched, that it is hash-verifiable, and how to use it to validate before acting. Nothing critical is missing for correct invocation.

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?

This tool has zero parameters, so there is no parameter burden for the description to carry. The input schema already states that no arguments are needed and the owner is derived from the authenticated principal. A baseline of 4 is appropriate for a zero-parameter tool.

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 a specific verb-resource pairing: fetch the AgentContractV1 descriptor and hosted_runtime facts, with the exact fields listed (version, schema_url, schema_hash). It is unambiguous about what the tool does, though it does not explicitly differentiate itself from sibling tools such as 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?

The description gives clear usage context: call this before acting to validate the platform contract by fetching schema_url and matching schema_hash. It also removes a common barrier by stating 'No API key needed — call this now.' It does not explicitly name alternative tools or state when not to use them, but the context is strong enough for an agent to act.

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