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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the shape of each result (slug, description, parameters, quota-unit cost per call), which matters because no output schema exists. No mention of rate limits or auth requirements, keeping 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 and dense with no filler; the purpose and the call_op handoff appear immediately. The long parenthetical category list is the only mild drag, but it carries real information rather than padding.

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, the description compensates by describing exactly what a match contains, and it bounds the search space with catalog size and categories. An agent has everything needed to call this and interpret the result.

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 query, category, and limit are already fully documented, and the baseline is 3. The description does add marginal value by enumerating all 11 valid category values (the schema only gives three examples), but adds nothing for query syntax or limit behavior beyond what the schema states.

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 (find upAPI operations), quantifies the catalog (99 operations across 11 named categories with example domains), and explicitly distinguishes itself from the sibling call_op, which executes rather than searches.

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?

Names the sibling and the workflow: find operations here, then 'Run one with `call_op`.' That is clear routing context, though it never states an explicit when-not case (e.g., when to go straight to call_op or to use web_search_post for generic web queries).

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