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

Annotations already establish readOnlyHint=true, so the description needn't argue safety; it instead discloses the shape of the payload (catalog of field properties) and that it answers permission questions about create/update/delete on the module. The inclusion of the underlying endpoint (GET /describe?elementType=<module>) reinforces that no state changes. It does not describe response nesting or error behavior, which keeps it below 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 sentences plus a short endpoint reference, with the payload contents front-loaded and the workflow hint second. It is tight, though the first sentence is a noun phrase without an explicit verb, which makes the opening slightly telegraphic.

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 carries the burden of explaining the return value, and it does so by enumerating the field attributes and the CRUD capability flags. For a one-parameter read-only introspection tool this is close to sufficient; only the structure of reference targets and picklist values is left unspecified.

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 coverage is 100% and the schema already explains the module parameter, gives examples (Contacts, Accounts, Leads) and points to vtiger_list_modules. The description's elementType=<module> phrase adds only a light mapping between the argument and the REST parameter, so it meets the baseline rather than exceeding it.

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 names the resource (a module) and enumerates exactly what is returned: field metadata (name, label, type, mandatory, editable, reference targets, picklist values) plus create/update/delete capability. This clearly separates it from vtiger_list_modules (which only lists names) and from vtiger_query/vtiger_list_records (which fetch data). The verb is implicit ('describe', telegraphed by the name and the GET /describe path) rather than stated outright.

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?

'Read this before creating or filtering' gives a concrete trigger that ties the tool to the create and query workflow. It does not name specific alternative siblings or exclusions, but the sequencing guidance is actionable enough for an agent to place this call first.

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