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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered. The description adds only that results contain id and name plus the underlying endpoint (GET /customdata) — modest extra context, no pagination or ordering detail.

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 short fragments, front-loaded with the payload description and ending with the endpoint. Nothing is padded, though the endpoint fragment adds little for an agent that only sees the tool interface.

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 parameters, full annotation coverage, and no output schema, the description is nearly self-sufficient — it even discloses the returned fields (id and name). Only the ordering/pagination behavior of the listing is unstated.

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 tool takes zero parameters, so the schema carries no semantics to supplement and the baseline is 4. The bracket '(id and name)' does slightly describe the return shape, but that concerns output rather than parameters.

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 resource (custom data fields) and scope ('All'), with a concrete payoff ('used as mail-merge values'). It doesn't explicitly distinguish itself from the singular sibling trumpia_get_custom_field, but the 'All' framing makes the listing role clear.

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?

Usage is only implied through the phrase 'used as mail-merge values'; there is no explicit when-to-use, when-not, or pointer to trumpia_get_custom_field for single lookups. Adequate but leaves the agent to infer the routing.

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