List Mail Users

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

'Side effects: None (read-only)' merely restates the readOnlyHint/destructiveHint=false annotations and earns little credit. It does add one piece of context the annotations do not carry — the return shape is a Markdown summary — but omits pagination behavior, result caps, and authorization requirements for the domain.

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?

Four labeled lines, purpose front-loaded, zero filler, and the endpoint is included compactly. Nothing could be removed without losing information.

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 one-parameter read-only list tool with full annotation coverage, the definition covers purpose, input, and output format. The remaining gap is pagination/result-limit behavior, which matters for a list endpoint but is a minor omission here.

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 description coverage is 100% and the single parameter is documented in the schema itself, so the baseline of 3 applies. The description only restates 'Inputs: domain' and adds no format, casing, or wildcard guidance beyond what the schema provides.

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 and resource ('List mailbox users for a domain') and pins the exact REST endpoint, so the agent knows it enumerates users rather than fetching one. It does not explicitly name siblings like fortimail.users.get or fortimail.users.create, leaving the list-vs-get distinction to be inferred from the verb and endpoint.

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 description implies its use case (enumerate mailbox users scoped to a domain) via the required 'domain' input, but offers no explicit when-to-use, prerequisites, or named alternatives such as fortimail.users.get for a single user. Usage is inferable but not stated.

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