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 fully covered. The description adds the concrete set of statistics produced, which is useful behavioral content absent an output schema, but says nothing about edge cases such as empty arrays, NaN handling, or minimum sample size.

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?

One dense sentence that front-loads the purpose and then lists the computed outputs. No filler, no repetition of the title, 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?

With no output schema, the enumeration of returned statistics does the work of describing the return value, and the single input is characterized as a numeric array. Only minor gaps remain (empty/degenerate input behavior, units or precision), so it is nearly complete for a simple read-only tool.

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 0% and there is a single required parameter 'data', but the description's phrase 'for a numeric array' effectively conveys the parameter's type and expected content. This compensates for the missing schema description without adding any further constraints or format details.

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 computation (summary statistics) on a specific resource (a numeric array) and enumerates exactly which statistics are returned. It does not explicitly contrast itself with siblings like distribution or confidence_interval, but the resource and output set are distinctive enough that an agent can identify it.

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?

There is no guidance on when to use this rather than the statistical siblings (distribution, confidence_interval, hypothesis_test). The description is purely a capability statement with no context, prerequisites, or alternatives named.

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