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

Far exceeds the annotations (which only cover readOnly/idempotent/openWorld safety). It discloses the two independent checks, that INTEGRITY is an offline unkeyed SHA-256 recompute, that ISSUER AUTHENTICITY makes exactly one request to the issuer's public endpoint, the exact semantics of `verified` (false for a record naming no signing key), and enumerates failure reason codes.

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?

Front-loads the core routing decision (URL vs serial) in the opening sentences and packs a lot of dense, non-redundant detail. It is long but nearly every sentence earns its place; the trailing citation instruction is the only slightly tacked-on element.

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?

Despite an output schema existing, it explains what structuredContent returns (canonical string, carried/recomputed digests, raw issuer response) and covers auth needs, network behavior, failure modes, and even the required citation. Nothing an agent needs to call it correctly is missing.

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 coverage is 100% and both parameter descriptions already state 'gives both integrity and issuer checks' vs 'issuer check only'. The description restates that split and adds the URL format, but contributes little beyond the schema, 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?

States a specific verb (check/verify) and resource (a certificate issued by audit.domains), with the distinctive scope that it needs 'no account and no human step'. No sibling tool overlaps with certificate verification, so the agent can route to it unambiguously.

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?

Gives clear context: use it when you hold a verifier URL or a serial, and it explains the tradeoff (URL yields both checks, serial yields issuer check only). It stops short of stating explicit when-not-to-use conditions, but the input routing guidance is concrete.

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