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

Annotations already cover the safety profile (readOnlyHint=false, destructiveHint=false). The description adds minimal behavioral context beyond stating it generates a palette; it doesn't mention return format, determinism, or side effects, but given annotation coverage, this is acceptable.

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?

Two sentences: the first states the core function, the second provides a sibling contrast. No filler, and the purpose is front-loaded. Efficient and well-structured.

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 simple tool with three fully-described parameters and no output schema, the description covers the essential usage. It could mention the output format (e.g., returns a list of hex colours) but that is not critical given the schema and sibling context. Overall complete enough for correct invocation.

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% – each parameter has a clear description and defaults. The description only repeats the base_color concept ('starting from one colour you choose') without adding new meaning, so it matches the baseline for fully-documented schemas.

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 a specific verb ('Build') and resource ('a set of colours that work together'), and explicitly contrasts itself with the 'Color Palette Extractor' sibling. This makes the tool's function unambiguous and distinct from related palette tools.

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?

It clearly frames when to use this tool vs. the extractor ('starting from one colour you choose' vs. 'pulls a palette out of a picture'), which gives context. However, it does not discuss alternatives among other generate_* tools (e.g., generate_gradient) or exclusions, leaving some selection ambiguity.

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