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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description adds real behavioral context by disclosing that it verifies the registry signature and freshness, and that the card proves registry facts only — not liveness. It omits auth requirements and rate limits, so not quite a 5.

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?

Two tight sentences, front-loaded with the fetch/verify action and the card contents, then the alternative path. Every clause carries information and none is wasted.

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?

No output schema exists, and the description compensates by naming the card's payload (identity, public key, bond) and the verification performed. For a two-parameter read tool with annotations covering safety, this is largely complete, though parameter-selection detail is thin.

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?

With 0% schema description coverage, the description partially compensates by saying the card is retrieved 'by botId or username,' signaling the two identifier options. But it adds no format, pattern, or mutual-exclusivity detail beyond that, leaving the schema's regexes as the only guidance.

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?

States a specific verb+resource ('Fetch a bot's Trust-signed card') and enumerates what the card carries (identity, public key, bond), plus the verification it performs. It also distinguishes this from the liveness-challenge path, so an agent can tell it apart from trust_get_challenge/trust_verify_signature without opening either schema.

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?

Explicitly routes the agent: use this for registry facts, but for proof the bot is live, 'also do a challenge (trust_get_challenge + trust_verify_signature).' Clear when-to-use vs an alternative. It does not state exclusions or how to choose between botId and username, which keeps it from being a full 5.

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