util_cbac

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the agent knows this mutates view state repeatably and safely. The description adds nothing beyond that: it does not say whether the coloring applies to all loaded objects or only the active one, whether other elements' colors are also changed, whether the change persists into saved sessions, or how it interacts with existing color settings.

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?

Very short and front-loaded, but the parenthetical '(Color By Atom, Cyan)' merely restates the preceding clause word for word, which is pure redundancy. The remaining text is a sentence fragment rather than a structured statement of behavior.

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?

The tool is simple (one optional parameter, output schema present, annotations supplied), so the low bar is nearly met. However, the key ambiguity — what the full color scheme is and how it differs from the nine sibling cb* schemes — is left unresolved, which is exactly the information an agent needs to choose and invoke correctly.

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% and the single 'selection' parameter already carries a description ('What to recolour. Defaults to everything.'), so the description is not required to document it. The description does not add selection-expression syntax or examples, so 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?

The description decodes the cryptic name: it colors atoms with a per-atom scheme in which carbons are cyan. That is a specific action with a specific visual outcome, but it gives no way to distinguish it from the many near-identical siblings (util_cbam, util_cbay, util_cbas, util_cbab, util_cbao, util_cbap, util_cbak, util_cbc, util_cbaw, util_cbag), which are presumably other color schemes. An agent cannot tell from this text alone which of the cb* tools to pick.

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?

There is no guidance on when to use this versus util_color_by_element, util_chainbow, util_rainbow, or the other cb* variants, and no mention of prerequisites such as an object being loaded or selected. Usage is only implied by the word 'Colors'.

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