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 returned field shape and the underlying REST endpoint, which is modest added context, but says nothing about empty-result behavior, pagination, or whether attributes with no value are included.

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 compact fragments with the resource scope front-loaded; nothing is buried. The trailing raw endpoint is marginally redundant with the tool name but still gives useful API provenance.

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 single-parameter read tool with full annotation coverage and no output schema, the description conveys both the scope (one client) and the returned fields, which is close to sufficient. Only edge-case behavior (empty lists, missing client) is left uncovered.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents client_id fully. The parenthetical '(id, name, datatype, value)' describes output fields rather than adding constraint meaning to the parameter, leaving this at the baseline.

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+resource: retrieves custom attribute values for one client, and even enumerates the returned fields (id, name, datatype, value). It is distinguishable from agendapro_list_custom_attributes (which lists attribute definitions), though it never names that sibling to make the contrast explicit.

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 phrase 'stored for one client' implies the required context (you must already have a client id), but there is no explicit when-to-use guidance and no mention of the closely related agendapro_list_custom_attributes or agendapro_get_client. Usage is inferable rather than stated.

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