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

Annotations already declare readOnlyHint=true, so safety is covered; the description contributes beyond that by disclosing the return shape (label plus a has-records indicator) and that results are scoped to the calling user's access rights. It omits ordering and error behavior, but for a no-argument read this is solid added context.

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 sentences, front-loaded with what is returned rather than what it is called. The trailing 'GET /listtypes' is an implementation detail of marginal use to an agent, a small amount of non-contributing content in an otherwise tight description.

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 and no output schema, the description must convey the return shape, and it does reasonably well by naming label and the per-module record indicator plus user scoping. It could be slightly more complete about the result ordering or how to consume the module names downstream, but nothing essential to calling it is missing.

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 semantic burden to compensate for. Baseline 4 applies; the description correctly conveys that it is an unfiltered enumeration.

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?

Names the resource (CRM modules) with a clear list semantics and concrete examples (Leads, Contacts, Accounts, Potentials, Cases), which lets an agent recognize the result set immediately. It doesn't explicitly differentiate from list_related_modules or describe_module, but the examples and the 'this user can access' scoping make the tool's identity unmistakable.

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 implied rather than stated: an agent can infer this is the discovery call to enumerate valid module names before calling describe_module or list_records, but the description never says when to use it or when to prefer list_related_modules. No exclusions or prerequisites are given.

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