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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered structurally. The description adds one genuinely new behavioral fact, the paid-plan entitlement, plus the scoring methodology. It says nothing about ordering of the response, tie-breaking, or how the default liquid universe is chosen.

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?

A single front-loaded sentence plus a short entitlement note; nothing is padded or repeated. The key differentiator (the scoring method) appears before the access caveat.

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 five-parameter, read-only analytical tool with no output schema, the definition covers the what and the method but not the shape of the answer (ranked list with scores? half-life units?) or the fallback universe behavior. Adequate, not complete.

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, formats, and the max-50 limit all documented in the properties. The description contributes no additional parameter meaning, which is the expected baseline when the schema already carries the burden.

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?

Names a specific analytical verb and resource (ranks currencies by mean-reversion strength) and even discloses the two underlying metrics, crossing frequency and reversion half-life. That is enough to separate it from siblings like analyze_volatility or analyze_drawdown, though no sibling is named explicitly.

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?

The only guidance is a plan gate ("Growth plan or higher"); there is no statement of when to reach for this analysis versus correlation, drawdown, or volatility tools. An agent must infer the choice from the metric name alone.

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