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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond that: it discloses which properties are evaluated, that hopping exposure is expressed as i7 x i5 combinations in use, and explicitly that it "never predicts a rate for your run" — a useful scope boundary. It does not describe the verdict output shape, but the output schema covers that.

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 guiding question ("Will this pool actually sequence?") followed by a dense but purposeful enumeration of the checks, then inputs and a sibling contrast. Every clause earns its place, though the hopping-exposure sentence is long and nested, slightly taxing readability.

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 zero-required-parameter, read-only analysis tool with an output schema present, the description is complete: it explains what is analyzed, the two input modes, how the error model and instrument shape the verdict, and how it differs from the builder sibling. Return-value detail is rightly left to the output schema.

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%, so the schema already documents every parameter including the pool-vs-kit mutual exclusivity ("Ignored when pool is given"). The description reinforces that both input paths exist but adds no syntax or format detail beyond what the schema provides, so the baseline of 3 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 (check) and resource (a pool of sample indexes) and enumerates exactly what verdicts it returns: duplicates, uniform length, distance guarantee vs claim, per-cycle color balance, index-2 orientation, and index-hopping exposure. It explicitly distinguishes itself from the sibling design_barcodes ("It CHECKS a pool; design_barcodes builds one"), so an agent can route correctly without opening either 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?

Names the alternative and the axis that separates them: check vs build, with design_barcodes as the builder counterpart. It also clarifies accepted inputs (a pasted list or a vendor kit by id). There is no explicit when-not or prerequisite guidance, so it falls just short of a full 5.

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