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

Annotations only supply destructiveHint=true, so the description does the explanatory work: it discloses that Formstack persists the prefill server-side and that the call returns prefilledUrl. That clarifies why the operation is marked destructive. It omits any note on permissions or rate limits, keeping it short of a 5.

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?

Two economical sentences lead with the outcome and follow with the storage/return behavior; the trailing API mapping is terse and useful for API-oriented agents. No rephrasing of the title or filler.

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 correctly names the returned artifact (prefilledUrl), and the rich input schema covers the nested field-value formats. Nothing essential for a correct call is missing, though permission/auth context is absent.

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% and the schema already documents field ID/value shapes, the form_id, and the optional incomplete_password, so the description adds no syntax beyond it. Baseline 3 is appropriate when the schema carries the parameter burden.

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 (Generate) and resource (link to a live form with prefilled fields) in the first sentence, and the API mapping (POST /forms/{formId}/prefill) pins the operation down. An agent can distinguish this from formstack_create_submission or formstack_get_form without opening a schema.

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 a concrete use case ('send a customer a form with their name and account number pre-entered'), which tells the agent when this tool is the right one. However, it never names an alternative or an exclusion (e.g. when to use create_submission instead), so it stops short of full when-to-use guidance.

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