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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds substantial context beyond that: the data-source restriction (daily turbocheck report, not turbometrics), the report-date vs scan-timestamp staleness gap of about a day, the write-to-read latency for triggered scans, and the meaning of a missing value (not a speed statement, not proof of never being scanned).

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?

Front-loaded with the answer to 'what is my value?' and every sentence carries distinct semantics (source, staleness, alternative, missing-value caveat). It is somewhat long and dense for a one-parameter tool, with heavy capitalization, but no sentence is pure 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?

With no output schema, the description carries the full burden and does so: it names the returned metric areas, the two timestamps returned, the staleness relationship, and how a missing measurement is reported. An agent has everything needed to call and interpret this tool 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 coverage is 100% and there is a single required 'domain' parameter already well documented in the schema. The description explains the returned areas but adds no syntax or format detail for the domain input beyond what the schema provides, so the baseline 3 is 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?

States a specific verb+resource: it returns ONE number per area (Overall, Speed, Images, Caching, WordPress, Technik, TTFB) and explicitly scopes the source to the daily turbocheck report. It distinguishes itself from siblings get_performance_findings and start_performance_scan by name, so an agent can route without opening schemas.

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?

Explicit when-to-use guidance: describes when a score is available (only after the nightly run), when it is NOT the right choice (a run just triggered via start_performance_scan will not appear here), and names the alternative (get_performance_findings) with the condition that selects it. Nothing is left to inference.

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