list_firewall_auth_sessions

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

With no annotations, the description carries the full burden and does reasonably well: it discloses the permission requirement and the failure mode (403), and 'list' implies a read-only operation. It doesn't discuss pagination, VDOM scoping behavior, or whether results are cached/live, which keeps it short of 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?

Front-loaded with the purpose, then the prerequisite, then compact Parameters/Returns blocks. The parameter block duplicates schema text and could be dropped, which is the only meaningful waste.

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 two-parameter read tool with no output schema, the description covers purpose, prerequisite, parameters, and the shape of returned fields (username, source IP, method, duration). An agent has what it needs to call it correctly; only edge behaviors like empty results or VDOM defaults are unaddressed.

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 both parameter descriptions are already in the schema, so the parameter list here largely restates it. The only value added is flagging vdom as optional, which makes this baseline-level rather than genuinely additive.

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 first sentence states a specific verb and resource: listing users currently authenticated against identity-based firewall policies. That is concrete enough to separate it from generic session tools, but it never names a sibling (e.g. list_active_sessions or list_ssl_vpn_sessions) to make the distinction 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?

It gives clear usage context by naming the prerequisite: an API profile with user-monitor permission, otherwise FortiOS returns 403. It doesn't state when to choose this over list_active_sessions or other session-listing siblings, so exclusions are missing.

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