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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful content about what each entry carries (nucleases and publication), but says nothing about coverage completeness, ordering, or whether the catalog is static — and with an output schema present, return-shape detail is not required.

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?

One tight sentence with the resource and its scope front-loaded and zero filler. It is a noun-phrase fragment rather than a verb-led statement, which slightly weakens the lead, but every clause (sourced, nucleases, publication) earns its place.

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 read-only catalog tool with an output schema and fully described parameters, the description covers what the tool returns and how broad the catalog is. The only real gap is the absence of any routing hint toward the many guide-design and library-listing 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 two parameters (_files, _subject) are already documented, and neither is required. The description adds no parameter meaning at all and reads like a no-argument listing tool, which does not prepare an agent for the optional project-record scoping the schema allows — baseline 3 applies when the schema carries the load.

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 names a specific resource (sgRNA scaffolds) and its scope ('every sgRNA scaffold this workbench has sourced'), plus the fields returned (nucleases covered, source publication). It is clearly distinguishable from design tools like crispr_design_guides or screen_guides, though it never names a sibling explicitly to draw the contrast.

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 word 'Every' implies a complete, unfiltered enumeration, which hints at how the tool should be used (look up available scaffolds rather than search a subset). But there is no explicit when-to-use statement, no mention of alternatives such as list_library or enzyme_collection, and no prerequisites or exclusion rules.

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