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

Beyond the annotations (readOnlyHint, openWorldHint, destructiveHint), the description discloses deterministic ordering, a bounded result cap of 5000, status fields (result_status/result_cap/total_status) for completeness, a quota of 1 token per row, and a dependency on a prior facets call. This is rich behavioral context that the annotations alone do not provide.

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 dense but well-organized, leading with the core purpose, then the workflow, then behavioral details, and finally quota. Every sentence adds value with no filler. The structure supports quick comprehension by an agent.

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 5 parameters, 2 required, and an output schema present, the description covers the necessary invocation steps, behavioral constraints, quota, and dependency on another tool. The output schema handles return structure, so nothing critical is missing.

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?

With 100% schema description coverage, the baseline is 3. The description adds meaning by explaining that param_key comes from the facets call, webmaster_id comes from search_webmasters, and values is an optional subset of normalized source values. It also clarifies the role of similarity_basis and rarity_count as output concepts, which helps the agent understand the data flow beyond 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 clearly states the specific function: finding webmasters that share normalized URL-parameter values with a source webmaster. It explicitly names the mechanism (url_parameter_overlap) and the required dependency on get_webmaster_similarity_facets, distinguishing it from sibling tools like find_similar_ads or search_webmasters.

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 provides a clear workflow: first call get_webmaster_similarity_facets, then pass one returned param_key, optionally narrowing to selected values. It gives explicit prerequisites and ordering but does not explicitly compare against alternative tools or state when not to use it, which would make it a 5.

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