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

Annotations already indicate destructive and idempotent behavior, and the description adds genuinely valuable behavioral detail on top: nested objects are merged, lists like recipients and rules are replaced wholesale, and plan-excluded features are refused with the dashboard's message. This goes well beyond what the annotations alone communicate, and there is no contradiction.

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?

Every sentence earns its place: core behavior, merge semantics, updatable blocks, sibling routing, and plan behavior. The most important constraint is front-loaded, and the description is appropriately sized for a complex update operation without padding or schema restatement.

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 complex nested update tool, the description plus rich annotations and schema cover what an agent needs to invoke it correctly. It explains update scope, destructive list replacement, and failure behavior for plan limits. It does not describe the response format, but since no output schema exists and the invocation behavior is well covered, this is a minor gap rather than a blocking one.

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?

The schema already documents each parameter in detail (roughly 90% coverage), so the description is not required to restate field meanings. It adds important cross-parameter semantics: partial updates merge nested objects but replace lists entirely, which materially affects how an agent should construct the payload.

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 precise action — updating a form with partial-change semantics ('Changes only what you pass') — and enumerates exactly which blocks and fields are updatable. It also distinguishes itself from sibling tools by noting that 'Webhooks have their own tools.' This makes it unambiguous versus update_webhook and create_form.

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 gives clear context for when to use the tool: modifying an existing form's settings, with nested objects merged and lists replaced. It explicitly routes webhook-related changes to separate tools, though it does not contrast with create_form or get_form, which is still fairly clear from the title and update semantics.

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