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

With no annotations, the description carries the full burden; it does disclose the return payload shape (grouped counts, average risk, high-risk counts), which is genuinely useful. However, it does not say how groups are ordered or what top_n truncates by, nor whether this is a permissioned read, leaving a material ambiguity for an 8-parameter aggregation.

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 short sentences, front-loaded with the operation and its output, then a usage example. No filler or redundant restatement of the title.

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 tool with 8 parameters, no annotations and no output schema, the description does well to describe the returned fields. But the ordering/truncation behavior behind top_n and the scope of the filters relative to grouping are unstated, leaving a notable gap for correct invocation.

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%, so every parameter including the dimension enum is already documented, and the description largely restates the dimension values. It adds no syntax or interaction semantics (e.g., how dimension interacts with the browser/os/device filters) beyond the schema, so the baseline 3 applies.

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 ("Group logins by a dimension") and enumerates the dimensions, plus what each group returns (counts, average risk score, high-risk counts). It is clearly an aggregation tool, implicitly distinct from get_recent_logins or get_login_stats, but it never names a sibling to sharpen the boundary.

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 line "Good for 'which browser has the highest risk'" gives a concrete selection scenario, which is real guidance rather than none. It offers no exclusions or explicit alternatives (e.g., when to use get_average_risk_score instead), so it stops short of a 5.

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