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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered by structured data. The description adds the cost signal ('Free') and scope of returned content, but says nothing about output size, whether the ruleset is static, or versioning.

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, with the cost qualifier and the subject front-loaded and no filler. The telegraphic fragment style ('The detection categories, rule counts and thresholds used by...') is slightly clipped but every phrase carries 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 zero-parameter, read-only reference tool with no output schema, the description adequately conveys what an agent gets back: categories, rule counts and thresholds. Only minor gaps remain, such as whether the ruleset changes over time.

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 there is nothing for the description to disambiguate and the baseline of 4 applies. The description does not introduce any input semantics that conflict with the empty schema.

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 precisely (detection categories, rule counts, thresholds) and ties it to the sibling tools that consume it, so an agent can tell it apart from scan_text and scan_tools. It reads as a noun phrase rather than an explicit verb+resource, which keeps it just short of a 5.

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?

'Free.' signals a cost distinction versus paid siblings and the reference to scan_text/scan_tools implies this is supporting documentation rather than a scanning action. However, it never states when to call it (e.g., before scanning to understand what will be detected) or any when-not condition.

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