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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the payload shape (type, options, where they apply) and the underlying GET /data-fields endpoint, but says nothing about pagination limits or rate behavior; the cursor hint lives in the schema instead. With annotations carrying the safety burden, this modest added context lands at 3.

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 tight sentences followed by the endpoint, with the resource definition front-loaded before the usage hint. No padding, though the raw "GET /data-fields" endpoint adds little for an agent that already has the tool name.

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 does carry the burden of describing returns, and it partially does so (type, options, applicability). Pagination is covered by the start_after schema entry. For a simple zero-required-parameter list tool this is close to complete, missing only explicit sibling routing.

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 80%, so the schema already documents q, limit, location_id and start_after; only external_id lacks a description. The description contributes nothing beyond that, though "where they apply" loosely gestures at the location_id filter. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (List) and resource (custom data fields), and clarifies the resource with a parenthetical that ties it to intake/booking form questions. The singular sibling waitwhile_get_data_field is implicitly distinguished by the list-vs-fetch framing, and the description names what the records contain (type, options, applicability).

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?

"Use the ids to read answers on visits" gives downstream context for the returned ids, which is genuinely useful. However, it never says when to use this tool versus waitwhile_get_data_field, nor any prerequisite or exclusion. Usage is implied by the list semantics rather than stated.

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