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

Annotations declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the agent knows it's a mutation with local scope. Description adds valuable context: plan restrictions (Pro for custom theme), preset-mode mismatch rejection, merge default behavior, and section structure. Does not disclose whether changes are immediately visible or require publish, which would be useful for a theme mutation.

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?

Front-loads the core operation and critical usage rule (preset preference, plan requirement) before detailing parameter combinations. Slightly dense with multiple bullet points, but every sentence carries essential operational guidance. Could be marginally tightened but no wasted content.

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?

With no output schema, the description covers the mutation semantics thoroughly but stops short of describing the return value (e.g., updated theme object or status). For a 5-param tool with 100% schema coverage, this is adequate, though an agent would still wonder what a successful call returns.

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 baseline is 3, but description goes further by explaining mutual exclusivity (preset vs theme), merge default and its ignored cases, reset semantics (theme: null), and section names with their purpose. This meaningfully supplements the schema's structural definitions.

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 clear verb+resource: set/patch/reset a form's theme for one color mode. It explicitly distinguishes from formTheme_get (read) by naming write operations and clarifies light/dark independence, which differentiates its scope within the theme tool pair.

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 explicit decision tree: prefer preset over custom theme, requires Pro plan for custom theme, pass exactly one of preset or theme, and explains reset vs patch vs replace semantics. No ambiguity about when to use each path.

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