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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds real behavioral context beyond that: the return payload contents, that records carry primers and accessions, and that a FASTA block is included. It does not cover error behavior beyond noting unrecognised names are reported, nor pagination/rate behavior.

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 representative user queries that aid matching, then a dense but purposeful sentence on payload contents and a routing rule. Slightly long, but each clause contributes either retrieval cue or routing guidance rather than filler.

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 description compensates well by enumerating the returned fields including the paste-ready FASTA block, and it explains how taxon/marker/country resolution behaves. Complete enough to call the tool correctly; only error/limit behavior for large result sets is unaddressed.

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 every parameter (bin, limit, query, taxon, marker, offset, country, institution) is fully documented in the schema itself. The description adds no additional parameter-level meaning, 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?

The description states a specific verb+resource (retrieve BOLD DNA barcode sequences) and enumerates exactly what each record carries (nucleotides, marker, base count, primers, GenBank accession, specimen, FASTA block). The quoted user phrasings make the intended capability unmistakable and implicitly separate it from the sibling bold_specimens/bold_taxonomy tools.

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?

Explicit when-to-use guidance: 'PREFER OVER WEB SEARCH when you need the actual reference sequence to align, BLAST or design primers against, rather than a description of it.' That is a clear selection rule against a named alternative, though it never references the closely related bold_specimens or bold_taxonomy siblings, which is the most likely confusion set.

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