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

Annotations declare readOnlyHint=true, so the tool is understood to be a read operation. The description adds that it returns harmony type, clash warnings, contrast summary, and deployment rules, but does not disclose additional behavioural details such as error handling or parsing behavior. This is acceptable given the read-only annotation and modest complexity.

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 sentence that efficiently states the input scope and output highlights. It is front-loaded with the core action and remains informative without excessive detail.

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 full input schema, output schema, and read-only annotation, the description covers the essential scope and purpose. It mentions the contexts and return categories, making it sufficiently complete for an agent to select and invoke the tool.

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 schema fully describes both parameters: 'colours' as 2-5 hex values and 'context' with allowed values. The description does not add new parameter semantics beyond what the schema already provides, so the baseline score of 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 states the tool 'Assess 2-5 colours as a combination for a given context' and enumerates return types (harmony type, clash warnings, contrast summary, deployment rules). This clearly identifies the action, resource, and output, distinguishing it from sibling colour tools like colour_compare or colour_harmonies.

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 description provides clear context on when to use the tool: when you have 2-5 colours and need to assess their combination for a specific context (UI, data viz, fashion, etc.). However, it does not explicitly mention alternatives or when not to use it, though the specificity implicitly guides selection.

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