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

Annotations already declare readOnlyHint=true, destructiveHint=false and a closed-world scope, so the safety profile is covered. The description adds that results include QC flags and cloning-enzyme conflicts and that the nuclease list is sourced from a real registry, which is useful context, but it says nothing about runtime cost, limits on number of guides returned, or scoring model used.

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 tightly written sentences with the action and its outputs front-loaded and no filler. It could arguably defer the registry remark, but nothing is 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?

With a rich schema and an output schema, the description needn't explain return values, and it does confirm the output character. However, for a tool with a nested subject object and advanced tuning parameters, the description gives no guidance on scoping, expected scale, or how it relates to the other CRISPR design/screen siblings.

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 the schema already explains _subject, _files, nuclease (with PAM details), min_stem, region_start/end, and restriction_enzymes. The description adds only a marginal note that nuclease values come from a registry, which does not extend meaning for the advanced region/stem parameters.

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+resource ('Design and score CRISPR guides') plus the concrete outputs it produces (on/off-target scores, QC flags, cloning-enzyme conflicts), so an agent knows exactly what comes back. It does not, however, differentiate itself from close siblings like crispr_design_library or screen_guides.

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?

Usage is only implied by 'on the subject' — the agent can infer this designs guides for a given sequence/record. There is no explicit statement of when to choose this over crispr_design_library, screen_guides, or search_off_targets, nor any prerequisites or exclusions.

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