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 structurally. The description adds the REST endpoint (GET /v3/custom_attributes) and the field list, but says nothing about ordering, pagination, or whether the list is bounded — minor gaps for a read-only enumerate call.

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 sentences: the payload description first, then the usage hint and endpoint. Nothing is wasted, though the trailing 'GET /v3/custom_attributes' is redundancy aimed at debugging rather than at an agent choosing a tool.

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?

There is no output schema, so the description carries the burden of describing the return shape — and it does, by naming all six fields returned per template. An agent can call this with confidence; only ordering or emptiness behavior is left 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 and the schema coverage is 100%, so there is nothing for the description to compensate for. Baseline 4 applies; no parameter-related confusion is possible.

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 concrete resource — the custom client field templates — and enumerates the returned fields (id, name, datatype, mandatory, group, choices), so an agent knows exactly what comes back. Combined with the title's 'List', the verb+resource is clear. It stops short of explicitly contrasting itself with the near-identically named sibling agendapro_list_client_custom_attributes, leaving that distinction to be inferred.

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 line 'Use the template ids when setting custom_attributes on a client' gives a genuine downstream-use hint, which is more than most list tools offer. However, it never states when not to use this tool or names the sibling agendapro_list_client_custom_attributes (which returns a specific client's values) as the alternative, so the choice between the two must be inferred.

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