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

Annotations already communicate read-only, open-world, idempotent, and non-destructive behavior. The description adds valuable context by calling the transparency log an immutable public record, noting the keyless signing aspect, and clarifying that results are entry UUIDs for rekor_entry. It does not contradict the annotations. A small gap is that it does not state how hash and email interact when both are supplied.

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 compact and front-loaded with the main purpose, followed by usage guidance, return behavior, auth context, and an example. Every sentence earns its place, and the 'PREFER OVER WEB SEARCH' rationale is genuinely useful rather than filler.

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 search tool with strong annotations and a fully documented schema, the description supplies the key missing context: what kind of inputs are meaningful, why this is the authoritative provenance source, and what the caller gets back (entry UUIDs for rekor_entry). It does not describe empty or both-parameter invocation behavior, which is a minor gap given there is no output schema.

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% with well-described parameters, so the baseline is 3. The description provides helpful framing like the types of artifacts a hash can represent and an example invocation, but it does not materially extend the schema's per-parameter explanations. It is adequate but not exceptional.

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 states a precise operation: given a sha256 digest, find every Sigstore transparency-log entry that signed it, and it also covers an email-based search mode. This is clearly specific and not a tautology. It references the downstream rekor_entry tool but does not explicitly contrast itself with rekor_entry_by_index or the other rekor siblings, so it falls just short of a perfect 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?

The description explicitly says to prefer this over web search for software supply-chain provenance, with a concrete rationale: package registries only know today's state, while this is the immutable public record. It does not spell out exclusions relative to the other rekor_* tools, but the tool name and 'returns entry uuids for rekor_entry' provide enough directional guidance.

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