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

Annotations declare readOnly/openWorld, and the description adds genuinely non-obvious behavior: private/deleted accounts are excluded by default, post-level engagement covers only a growing subset, qualified sorts apply recency/reach/sample-size/sanity thresholds, include_email only works for entitled keys, and cost is 1 credit per record with a minimum of 2. This is far more than the annotations convey.

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?

Dense but front-loaded: it leads with what the tool returns, then constraints, then the alternative. Every sentence largely earns its place except the top_sounds clause, which is output-schema territory and not a parameter an agent can set here.

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 12 parameters, 100% schema coverage, and an output schema, the description covers everything an agent needs: filtering behavior, default exclusions, sort tradeoffs, cost, and the sibling alternative. Return-value detail is correctly left to the output schema.

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 baseline is 3, but the description adds real meaning beyond the schema for sort (contrasting engagement_desc vs engagement_qualified_desc tradeoffs) and ties page_size to credit cost. Minor deduction because the top_sounds sentence references behavior not tied to any listed parameter, adding slight ambiguity.

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 (Search) and resource (indexed TikTok creator records) plus scope (profile filters, follower/engagement ranking). Explicitly names the sibling to use for YouTube creators, so an agent can distinguish it without opening either schema.

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?

Gives explicit when-to-use guidance: prefer engagement_qualified_desc for best-engagement leaderboards, use handle over q for known accounts, set include_inactive=true only for historical lookups, and route YouTube queries to datasets_youtube_creators_search. Includes both selection criteria and the reasoning behind them.

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