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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the one trait annotations cannot express: the returned data is fabricated and must never be surfaced as real lines, which is the critical behavioral caveat for this tool.

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, zero filler, with the identity of the data front-loaded before the misuse warning. Every clause earns its place.

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 10-parameter read-only tool with full schema coverage and no output schema, the description supplies the essentials: what the payload is, that it mirrors the live shape, and that it must not be reported as real. It could note that filters still apply to a fixed fictional dataset, but nothing critical is missing for correct invocation.

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 enums and defaults documented for status, tier and limit, so the schema carries parameter meaning on its own. The description adds nothing about how stat/league/tier/cursor behave on sample data, nor whether filters meaningfully reduce the fixed sample set — that ambiguity is left unresolved.

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 states a specific verb-like behavior and resource: it returns fictional sample rows shaped like the live response, explicitly for keyless trials. That distinguishes it cleanly from get_projections and the other data siblings, and the 'Never present these as real lines' clause adds a scope boundary an agent can act on.

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?

'For trying the API without a key' gives a clear selecting condition, and the warning implies these rows are not for real analysis. It stops short of naming the alternative (get_projections) or explicitly saying 'do not use once authenticated / when the user needs actual lines', so the exclusion 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.