url_category_usage

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

Annotations already declare readOnlyHint and destructiveHint, so the [READ-ONLY] prefix adds no new credit. The description does add useful behavioral context beyond the schema: rule ordering is shown 'in evaluation order when device is set', and it specifies exactly which rule/profile references are returned. No contradiction with annotations exists.

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?

The description is a single dense sentence that front-loads the read-only intent and core purpose before the detailed clauses. It contains no filler, though the nested 'with the rules using those profiles' clause makes it slightly harder to parse than necessary.

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 output schema present, the description still explains what the result contains: security/decryption rules, URL filtering profiles, and rules using those profiles. Parameter behavior is fully covered by the schema, and the device-dependent ordering detail adds needed context. It does not describe no-match behavior or result formatting, but those are minor gaps for this read-only usage query.

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%, so all four parameters are already documented with meaning and constraints. The description adds only a device-related behavioral note about evaluation order, which is useful but not sufficient to move far above the baseline set by the 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?

The description states a specific verb/resource combination: it 'Shows where URL categories are used' and then enumerates the exact reference surfaces: security/decryption rules and URL filtering profiles. This clearly distinguishes it from sibling tools like get_url_categories, url_category_get, url_category_find, and test_url_category.

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 intended use is implied by 'Shows where URL categories are used', but the description provides no explicit when-to-use instruction, no exclusions, and no named alternatives. An agent can infer the use case, but the description does not proactively route it away from nearby category-lookup siblings.

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