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

No annotations are provided, so the description carries the full burden. It does disclose the output type (a CSS string) and implicitly a pure, side-effect-free transform, which is the main behavioral fact for this tool, but it omits the default angle behavior, the minimum two-stop requirement, and whether output is validated/sanitized.

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?

A single front-loaded sentence with zero filler; the resource and required inputs appear immediately. Nothing is repeated from the schema and nothing extraneous is included.

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 two-parameter pure function with no output schema, the description conveys the resource, the inputs, and the return type, which is nearly everything needed. The remaining gap is the stop-item semantics (color format and position scale), which the schema only partially covers.

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 only 50%: angle is documented in the schema ("Degrees; 0 = top-to-bottom") but stops and its color/position fields are not. The description names both parameters but adds no format detail (color syntax, position units, stop ordering) beyond what the schema already structures, so it only partially compensates for the gap.

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?

States a specific verb ("Build"), a specific resource ("CSS linear-gradient string"), and the inputs it consumes ("color stops + angle"). Among siblings it is the only gradient builder, so it is unambiguously distinguishable from css_box_shadow_build, css_border_radius_build, and css_format.

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 description says what the tool produces but gives no when-to-use context, no prerequisites, and no alternatives (e.g., when to hand-write CSS vs. use css_format). The agent must infer that this is the tool to reach for whenever a linear gradient string is needed.

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