util_cbap

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

With no annotations, the description carries the full burden of disclosure. It states the visual outcome ('purple carbons') but does not explain whether it recolors all atoms by element, whether it overwrites current colors, how it interacts with the 'selection' parameter, or any side effects. The phrase 'Colors by atom' is ambiguous about scope.

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 description is a single compact sentence, front-loaded with the core action. There is no wasted text, though the phrasing is slightly awkward and omits important context that would make it more useful. It earns a 4 for efficiency rather than a 5 due to the terse and incomplete nature.

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?

This is a simple tool with one optional parameter and an output schema, but the description is minimal. It does not explain how it differs from the many sibling utilities (e.g., util_cbag, util_cbab) or clarify the exact coloring behavior. It is adequate for a basic utility but leaves gaps for users unfamiliar with PyMOL conventions.

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?

The input schema has 100% coverage for the single 'selection' parameter with its own description ('What to recolour. Defaults to everything.'), so the baseline is 3. The tool description adds no additional meaning about the parameter, but does not need to because the schema already explains it.

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 'Colors by atom, purple carbons' clearly states a specific verb (colors) and resource (atoms, specifically carbons in purple). It distinguishes from generic 'color' and other utility tools by naming the purple carbon scheme, though it could be more explicit about coloring all atoms by element with carbons purple.

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?

No guidance is provided on when to use this tool versus the many similar sibling utilities like util_cbag or util_cbc. The description merely states what it does, leaving the user to infer usage context from the name and existing knowledge.

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