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

Beyond the annotations, it discloses pricing ($0.01 per scored lookup), the free-and-signed case for agents with no history, that results are signed verification history, and the exact shape of the score (recency-weighted with 95% confidence interval). The cost disclosure also explains the otherwise puzzling idempotentHint=false for a read-only tool: repeated lookups incur charges.

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?

Purpose and use case are front-loaded, followed by return contents and then pricing, which is the right order. Slightly dense, with the closing 'a lookup for an AI agent with no history is answered free, signed' reading as a fragment, but no sentence 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?

With no output schema, the description compensates by naming every returned field (verified/passed/failed counts, last seen, weighted score with confidence interval) and by stating the cost model. An agent has everything needed to decide to call it and to interpret the response.

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?

There is a single parameter with 100% schema description coverage, including the 'test-' reservation and format constraints, so the schema carries the full burden. The description adds nothing about agent_id itself, so baseline 3 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 first sentence pairs a specific resource ('verification record' / 'trust score') with a concrete action ('check ... before you hire it'), and the second enumerates the exact contents returned. It is unambiguous what the tool does, but it never names the sibling verify_schema, so an agent must infer the boundary from the description alone.

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 gives concrete triggering situations: 'before you hire it, rely on its output or pay it' and 'Check a counterparty before you pay.' That is strong when-to-use guidance. It offers no explicit when-not condition and does not point to verify_schema as the alternative for schema/verification checks.

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