Match themes to brand colors

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

With no annotations provided, the description takes on full responsibility. It discloses the tool is 'Read-only and free,' states a core behavioral limitation 'ranks on color alone and ignores mood, audience, and use case,' and warns the output is a shortlist needing further validation. This is highly transparent.

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 appropriately compact—three sentences that front-load the core purpose, then provide usage guidance, limitations, and alternatives. Every clause adds value; no wasted words or redundancy.

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 only two parameters and no output schema, the description covers all critical aspects: purpose, relevance, limitations, complementary actions, and safety. It gives enough context for an agent to know when and how to invoke it, and what to do with the results.

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 already provides 100% description coverage for both parameters, so the baseline is 3. The description reinforces the meaning of 'colors' (brand colors the user owns) but adds no new syntax or formatting details beyond the schema, which is sufficient.

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 opens with a specific verb 'Rank' and clearly identifies the resource 'published kits' and the scope 'by how close their palette sits to colors the user already owns, using perceptual color distance rather than string matching.' This precisely distinguishes it from siblings like list_themes or search_themes, which do not rank by color fit.

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?

Explicitly states when to use: 'when a brand has existing colors that the design system has to live with.' It also gives a clear exclusion: 'When the user has no fixed colors, list_themes or search_themes will serve them better.' Additionally, it advises to 'check the rest of the fit with get_design_md before committing,' naming the complementary tool.

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