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

The description goes well beyond the readOnlyHint annotation by detailing what the tool computes and returns: archive grounding, verdict, brand fit, market risk, category cliche check, material behaviour, copy hooks, and usage rules. It also lists the structured output fields and provides concrete examples. No contradiction with annotations.

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 dense but well-structured: it opens with the one-line purpose, then lists the combined analyses, inputs, outputs, and examples. Every sentence provides essential information, and the use of 'Input:' and 'Output:' labels makes it scannable. No wasted words.

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 tool with 5 parameters, nested objects, and an output schema, the description is remarkably complete. It covers all input types, enumerates the major output sections, and gives four varied examples. The existence of an output schema reduces the burden to explain return values, so this description is fully sufficient for an agent to select and invoke the tool 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?

The schema has 100% parameter description coverage, so the baseline is 3. The description's 'Input:' line simply recaps the parameter names already present in the schema (hex, brand_context, constraints, markets, medium) without adding new semantic detail. It does not deepen the meaning of any parameter beyond what the schema already provides.

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 clearly states a specific verb+resource: 'Single-call commercial colour strategy report.' It enumerates the combined analyses (archive grounding, verdict, brand fit, market risk, etc.), which distinguishes it from the many sibling tools that focus on individual aspects. This is a definitive, non-tautological purpose.

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 phrase 'Single-call commercial colour strategy report' clearly implies using this tool when a complete strategy is needed in one call rather than assembling it from separate tools. However, it does not explicitly name alternatives or state when not to use this tool, so it falls short of a 5.

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