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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), so the bar is lower, and the description adds genuinely new behavioral context beyond them: the record is signed, the score is recency-weighted with a confidence interval, and lookups are paid at $0.01 each. The cost/payment requirement is the key operational detail an agent wouldn't otherwise know.

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?

Three front-loaded sentences with no filler: purpose first, then usage contexts, then pricing. Every sentence carries information, though the phrasing is slightly terse/jargon-dense.

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 read-only, single-parameter tool with no output schema, the description supplies the return payload (counts, last seen, score with CI) and the pricing model, which is everything an agent needs to decide and invoke correctly.

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?

Schema description coverage is 100% and the single agent_id parameter is already richly documented in the schema (including the test- prefix reservation). The description adds no parameter-level semantics, so the 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 description names a specific verb+resource (returns an agent's signed verification history) and enumerates exactly what comes back: verified/passed/failed counts, last seen, and a recency-weighted score with a 95% CI. It does not explicitly differentiate itself from the sibling verify_schema, so it stops short of 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?

It gives concrete when-to-use contexts: 'Use before relying on another agent' and 'Check a counterparty before you pay, or see the record buyers will see.' That is clear usage framing, but it never names the alternative verify_schema or states when NOT to use this tool.

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