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

Annotations already declare readOnlyHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds that output is an N×N grid of every ordered pair computed with the exact k-mer engine, which hints at the N² cost, but it does not warn about the sequence-count/residue refusal thresholds or that the subject record is included by default — both matters the schema carries alone.

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 tightly written sentence with the operation, the engine and the payoff front-loaded in that order. Nothing is redundant or padded, and the visual framing ('in one picture') earns its place by conveying the output form.

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 13-parameter tool with nested _files/_subject objects and an output schema, the description is terse but the schema and output schema carry the mechanical detail. The one real omission is that it never mentions the subject record joining the set by default (include_subject), which affects what the grid actually contains.

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 explains sequences, word_size, max_sequences and include_subject in detail. The description contributes only the term 'k-mer engine' without mapping it to word_size or clarifying the set-membership semantics of sequences/_files, so the baseline 3 applies.

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 and resource ('all-against-all dot plot over a sequence SET') and pins the underlying engine (EMBOSS polydot). The 'SET' and 'every ordered pair' phrasing implicitly separates it from the single-pair sibling dot_plot, but it never names that sibling, so the differentiation is inferential rather than explicit.

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?

Usage is only implied through the benefit clause ('shared regions, repeats and inversions across a whole family are visible in one picture'), which suggests family-scale comparisons. There is no explicit when-to-use, when-not-to-use, or pointer to dot_plot for a single pair, even though that is the obvious alternative in the sibling list.

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