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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable behavioral context: no authentication required, the response is equivalent to /.well-known/agent.json, and the descriptor is hash-verifiable. 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?

The description is two sentences, front-loads the most important call-to-action, and avoids excessive detail. The second sentence packs both equivalence and validation guidance, which is slightly dense but still concise and purposeful.

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?

With an output schema present, the description does not need to enumerate return fields. It covers purpose, access requirements, endpoint equivalence, and how to perform contract validation before acting, making the tool self-sufficient for an agent.

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 covers the input space completely and the description does not need to explain parameter meaning. This matches the baseline for a no-parameter tool; nothing is missing here.

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 (version, schema_url, schema_hash) plus hosted_runtime facts — with a specific verb. It does not explicitly differentiate this from the sibling verify_contract tool, though the mention of fetching rather than verifying suggests the boundary.

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: 'No API key needed — call this now' and 'before acting' indicate this is an early, low-friction discovery step. It does not explicitly state when not to use it or name alternatives, but the timing guidance is concrete and useful.

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