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

With annotations already declaring readOnly, idempotent, and non-destructive behaviour, the description adds that the tool returns 'the gradient value and a full background declaration,' which is useful beyond the structured metadata. It does not discuss edge cases, but the annotations cover the safety profile.

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?

At about 40 words, the description is front-loaded with the result, states options in the second sentence, and gives output/source context in the third. Every sentence contributes.

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 generator with a fully documented schema, an output schema, and clear annotations, the description plus structured metadata covers what the tool does, its inputs, its output, and its safe read-only nature. No essential selection or invocation detail is missing.

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%, so the parameter schemas already carry the meaning; the description adds only a slight reinforcement ('two colours', 'angle in degrees', linear/radial). This meets the high-coverage baseline but does not meaningfully augment parameter details.

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 action ('Build a ready-to-use CSS gradient from two colours') and names the two supported forms ('linear gradient with an angle in degrees, or a radial gradient'), which is enough to distinguish it from the many colour-related sibling 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 gives clear context: use when you need a ready-to-use CSS gradient from two colours, with explicit choice between linear and radial. It does not explicitly name alternatives or state when not to use it, so it stops one short of a full routing explanation.

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