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

Annotations already declare readOnlyHint=true, and the description adds valuable behavioral context: it accepts up to 20 hex values, automatically deduplicates, and returns a full Colour Passport with listed components. It does not describe error behavior for >20 or invalid hexes, but this is acceptable given the read-only nature and output schema.

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 concise and well-structured. It immediately identifies the tool as a batch version, then explains the input limit, output contents, deduplication, and use cases. Every sentence adds essential information without unnecessary filler.

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?

Given the output schema exists, return values don't need detailed explanation. The description covers the main use cases, input constraints, and deduplication behavior. It is complete enough for a batch tool but could optionally mention error handling for excessive inputs or invalid hex values.

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%, so the baseline is 3. The description adds meaning beyond the schema by highlighting the 'up to 20 hex values' limit and the automatic deduplication behavior, which directly clarifies how the hexes array input is processed.

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?

Clearly identifies itself as the batch version of colour_passport with a specific verb+resource+scope: submit up to 20 hex values and receive full Colour Passports. It distinguishes itself from the singular sibling tool by explicitly mentioning batch processing and deduplication.

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?

States exactly when to use this tool: multi-colour workflows, Figma palette analysis, or any case where calling colour_passport separately would be slow. This explicitly points to the alternative (colour_passport) and provides clear use cases.

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