parse_dna_segments

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

Annotations only declare readOnlyHint and openWorldHint, so the description carries the real behavioral burden and delivers: it discloses the return shape ('each segment plus the total and largest-segment centiMorgans') and, critically, the failure contract ('parsed is false and the reason is given'). It also explains the semantic trap the server's silent zero-segment/success response would otherwise create, which is exactly the kind of insight annotations cannot convey.

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?

Three tight sentences, front-loaded with the action, then the result, then the failure semantics. Every sentence adds distinct value and none is redundant padding.

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 still conveys what is returned (segments, total cM, largest segment) and how failures are signaled (parsed=false plus reason). Combined with a fully documented input schema and read-only annotations, an agent has everything needed to call and interpret this 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 100% and the schema description already spells out the row format (chromosome, start, stop, centiMorgans, SNPs, comma/tab separation, M/P/U side, tolerated header). The prose adds no format detail beyond that, so the baseline of 3 for a fully documented single parameter 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 ('parse pasted shared-segment data into structured segments and totals') and clarifies the intent of checking a match file's contents. It is clearly distinguishable from the neighboring DNA tools like add_dna_match and get_dna_matches, which respectively write and retrieve matches rather than parse raw pasted text.

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?

Explicitly says to use it 'to check what a match file actually contains before recording it,' which names both the context and the downstream action (recording via add_dna_match). It stops short of naming the alternative tool or stating when not to use this, but the situational guidance is clear.

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