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

Annotations already establish the safety profile (read-only, idempotent, non-destructive, closed-world), so the bar is lower. The description contributes the shape of the result set, which is genuinely useful, but offers no information on result volume, ordering, or behavior for an account with zero monitors.

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?

Two short sentences, front-loaded with the action and the returned fields, with the auth note trailing. Nothing is redundant or padded.

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 one-optional-parameter read-only listing with no output schema, the description appropriately enumerates what comes back, compensating for the missing output schema. It stops short of covering ordering or pagination, but nothing an agent needs in order to call it correctly is absent.

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 optional parameter at 100% schema coverage, so the schema already does the work, including the header-based alternative to passing api_key. The description's "An API key is necessary" adds nothing beyond the schema and is actually weaker than the schema, which says the key is unnecessary when sent in the Authorization header.

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 gives a specific verb and resource ("List the monitors of the account") and immediately enumerates the returned fields: current status, last response time, and SSL certificate expiry. This distinguishes it from single-target siblings such as check_ssl and check_website, which check one thing rather than enumerating all monitors.

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?

Usage is only implied – an agent can infer you call this to get an overview of all monitors. There is no explicit when-to-use versus siblings like get_account or service_status, and no caveat about empty accounts or when a per-site check is preferable. The only guidance offered is the auth prerequisite.

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