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

Annotations already cover the safety profile (readOnlyHint true, openWorldHint false), yet the description adds real behavioral context the annotations lack: results are tier-gated, with Pro plan incidents carrying an AI diagnosis while Free plan incidents return ai_locked. That is exactly the kind of response-shape nuance an agent needs to interpret output and explain it to a user. It stops short of noting ordering or what happens when no incidents exist.

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 sentences, zero padding: the first front-loads what is returned, the second adds the plan-gating caveat. Nothing is repeated from the title or schema, and every clause carries information.

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?

With no output schema, the description correctly takes on the job of describing return values and does so field by field, including the ai_locked marker. It leaves minor gaps around ordering, truncation by limit, and empty results, but for a straightforward read-only history tool it is nearly sufficient.

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%, with defaults and max ranges documented for days and limit and the provenance of website_id spelled out, so the schema carries the parameter burden. The description's word "recent" loosely hints at the days window but adds no format or semantics beyond the schema, making the baseline 3 correct.

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 ("Returns recent outages for one monitored website") and even enumerates the returned fields (start, end, duration, error), which makes it clearly distinct from check_website or list_monitors. It never explicitly names a sibling or states the contrast, so the differentiation is inferred rather than stated.

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 implied — this is the tool for reviewing past incidents on a known website_id — but there is no explicit when-to-use versus when-not, and no guidance such as "use check_website for current status" or "use list_monitors to find the website_id first." An agent can infer intent but must reason about the alternative themselves.

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