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

Annotations only declare readOnlyHint=false, destructiveHint=false and openWorldHint=false; the description adds no behavioral context such as whether designs are persisted, what the output looks like, or how refusal behaves for oversized windows. That refusal behavior and the degeneracy coercion are genuinely useful traits, but they live in the schema rather than the description, so the description adds little beyond structured data.

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 sentence that front-loads the action and the required input before the motivating scenario. No restatement of the title, no filler, nothing wasted.

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 17-parameter tool with a rich schema, an output schema, and an upstream alignment dependency, the description establishes the job and the input contract adequately. It does not hint at the algorithm trade-off (wrm randomness vs exhaustive refusal) that dominates correct invocation, leaving that entirely to the schema, which is dense but self-contained.

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 every parameter already carries its own detailed prose, including units, defaults, and algorithm dependencies. The description contributes only the idea that aligned (gapped) rows are required input, which the `alignment` and `alignment_fasta` schema entries already say. Baseline 3 is appropriate.

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?

Names a specific verb and resource ('design degenerate primers') and pins the required input ('from a multiple-sequence ALIGNMENT'). The framing sentence 'amplify every homologue in this family' plus the contrast with a 'single-template designer' separates it from the many other primer-design siblings at a glance.

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?

Gives a clear selection rule: use this when the goal is to amplify every homologue in a family from an alignment, because single-template designers only see one sequence. It does not name the specific alternative tools (design_primers, design_primer_pairs, design_bisulfite_primers) or state exclusions such as what to do when no alignment exists, so it stops short of full routing guidance.

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