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

Annotations already declare this a safe, non-destructive, closed-world read/compute operation, so the safety profile is covered. The description adds that the output is primers with enzyme site, spacer and overhang on a Tm-matched footprint, but says nothing about how many primer pairs come back, degeneracy, or failure conditions such as an overhang that cannot be Tm-matched.

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?

Two sentences, both front-loaded with the action and its purpose, with no filler. The second sentence is dense but does real routing work rather than restating the name.

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 design tool with an output schema, full parameter coverage, and clear annotations, the description covers purpose, inputs conceptually, and sibling relationship. Minor gap: no mention of expected output shape or the consequences of an overhang length mismatch, though the output schema carries the return structure.

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%, so every parameter including enzyme, target_tm, buffer_bases, and the overhangs is already documented in the schema. The description reinforces the concept (four-base overhang, Tm-matched annealing footprint) but adds no syntax, format, or constraint detail beyond what the schema provides; 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: designing PCR primers that add Type-IIS fusion sites (enzyme site, spacer, four-base overhang) onto a Tm-matched annealing footprint. It also situates itself relative to a named sibling, so the agent can distinguish it from the many other design_* primers tools without opening a 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?

Clearly frames the use case — converting a sequence that is not yet a Golden Gate part into one — and explicitly pairs it with check_golden_gate_parts as the complement (that one rejects parts, this one creates one). It stops short of naming alternatives such as design_gibson_primers or design_primers, so there is no explicit when-not guidance.

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