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

Annotations already cover the safety profile (readOnly, non-destructive, non-open-world), so the description's job is to add context — and it does: the ~7-day window for failure categories and the fact older failures fall back to 'uncategorised' is a real, non-obvious data caveat. It stops short of noting ordering, latency, or empty-result behaviour.

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 filler. The core purpose and return shape are front-loaded, and the second sentence is a genuine caveat that earns its place rather than padding.

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 carries the burden of describing returns and does so — counts by failure category and status, plus the failing tests with build and environment. Combined with the fully documented input schema and safety annotations, an agent has everything needed to call this correctly.

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 limit, fromDate and toDate all fully documented including defaults and the 59-day bound. The description only restates 'date range' generically and adds no format or boundary detail 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 (summarises) and a tightly scoped resource (failed and errored web automation tests) plus the exact breakdowns returned, which separates it from broad analytics tools. However, it never names the neighbouring tools (getAnalyticsData, getFlakyTests, getTestTrends), so an agent must infer the distinction from scope alone.

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 rather than stated: the 'date range' framing and the failure-only scope let an agent infer it is for troubleshooting recent failures. There is no explicit when-to-use, no when-not-to-use, and no pointer to alternatives such as getTestTrends for pass/fail trends or getFlakyTests for intermittency.

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