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

Annotations already declare this is a safe read-only op, so the description correctly spends its words elsewhere: it discloses the default window (30 days), the sort order (soonest first), and the non-obvious inclusion of already-expired items. That last detail is genuinely useful behavior an agent could not predict. The only miss is that it does not say what happens at the 0 boundary or whether results are paginated.

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?

A single sentence of roughly twenty words that front-loads the resource and the window, then appends the two behavioral caveats. Nothing is redundant and nothing is buried.

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?

There is no output schema, so the description is the only place an agent can learn what a result row contains (asset name, expiry date, days remaining, type). It omits that, and also omits the `type` filter, so a caller cannot fully predict the shape of the response. Adequate for deciding whether to call it, thin for interpreting the result.

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 0%, so the description needs to carry parameter meaning. It documents `days` well (default 30, semantic of the window) but never mentions the `type` enum filter (domain vs. ssl), leaving the agent to infer that this argument exists and what it does from the schema alone. The 3650 maximum is also undisclosed, though the schema carries it.

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 resource (domains and SSL certificates) and a specific condition (expiring within N days), which is enough for an agent to distinguish it from lookup_domain, lookup_cert and list_assets. It does not name a sibling or contrast explicitly, which keeps it out of the top band.

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 expiring-window framing implies when to use it (a proactive expiry check rather than a specific-asset lookup), but there is no explicit when-to-use/when-not-to-use or pointer to lookup_domain/lookup_cert for single-asset detail. Usage is inferable rather than stated.

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