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

Annotations cover the safety profile (idempotent, non-destructive, open-world), so the bar is lower. The description still adds real value: it discloses partial-update semantics ('send only the fields to change') and a required read-reconnaissance step before writing, which the annotations do not convey.

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?

Three sentences, front-loaded with the goal, then the workflow, then format rules and a doc pointer. Every sentence carries information; the external URL is a minor efficiency trade-off but earns its place by offloading the full field list.

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 mutation tool with no output schema, the description plus annotations cover safety, prerequisites, update semantics, and color format. The only gap is return/confirmation behavior and the meaning of enum-like values (borderRadius, size), which the schema 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 coverage is 100% and the nested style object documents every field, so the baseline is 3. The description goes beyond that by specifying accepted color syntaxes (#hex, rgb(), hsl(), CSS names) and noting each color has a Light and Dark variant, which the schema does not state.

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 and resource — restyle the language menu to match the site's look — which an agent can distinguish from the broader proxylang_change_site. It stops short of explicitly contrasting with any named sibling, so it lands at clear-but-undifferentiated.

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?

Gives an explicit prerequisite workflow: read the site's brand color, background, text color, roundness and dark mode first, then send only the fields to change. That is actionable context, though it never names alternatives or states when not to use this tool.

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