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

The annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds that it returns candidate primer pairs with Tm/GC, but it omits design defaults, constraints, and whether the 'gene' path performs an external lookup.

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?

The definition is compact and front-loads the actionable 'USE WHEN' instruction. The bilingual title and alias list add some repetition, but they are short and useful for tool matching rather than wasteful prose.

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 low-complexity, two-parameter read-only tool, the description covers purpose, trigger, and a basic return summary. It still leaves meaningful gaps around default primer-design parameters and the logical requirement to provide either a gene or a sequence.

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%, and the schema explicitly documents both 'gene' and 'sequence', so the baseline is 3. The description groups them as alternative input sources but does not state what happens if both are supplied or that at least one is logically required despite the empty required list.

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 gives a specific verb and resource ('design PCR primer pairs') and names the input sources ('DNA sequence or gene') plus relevant outputs ('Tm, GC, product size'). It is clear on its own, but it does not explicitly distinguish itself from nearby siblings such as primer_tm or qpcr_bayesian_design.

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?

The 'USE WHEN' line gives a clear triggering condition: designing PCR primer pairs from a sequence or gene. It does not provide when-not guidance or name alternatives, so an agent must infer whether primer_tm would be more appropriate for Tm-only requests.

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