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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds substantial non-obvious context: the source is a once-daily report rather than live data, the report date and the embedded scan timestamp are routinely one day apart, and a missing value means 'no measurement' rather than slow or never-scanned. That is exactly the kind of freshness/caveat disclosure annotations cannot express.

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 does it return', then the source and freshness caveats. It is dense for a one-parameter read tool and slightly repetitive in restating the routing, but every sentence carries real information, so it is not 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 read-only, single-parameter, no-output-schema tool, the description covers purpose, source, freshness semantics, sibling routing, and the meaning of missing values. Nothing an agent needs to call it correctly or to interpret the result is missing.

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 required parameter (domain) with 100% schema description coverage, so the schema already documents it. The description adds nothing about the domain format beyond the schema's own example, so the baseline 3 for fully-covered params is appropriate.

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 (returns one score per area) and enumerates the areas (Gesamt, Speed, Bilder, Caching, WordPress, Technik, TTFB). It also names the data source (daily turbocheck report) and explicitly distinguishes itself from get_performance_findings and start_performance_scan, so an agent can tell it apart from siblings without opening any schema.

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?

Gives explicit when-to-use routing: use this for the scored daily value, use get_performance_findings for the last actually-run scan, and a start_performance_scan run only appears here after the next nightly pass. It also explains that divergence between the two tools' numbers is expected and not an error.

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