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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description still adds the materially useful 'Free' cost signal versus paid unlocking. It also discloses that returns include the user's unlock access and remaining leads, which is behavioral context not present in any annotation. It does not state whether the facet counts respect the uid/view parameters or how heavy the aggregation is.

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 purpose is front-loaded in the first clause, which is good, but the middle is a single sprawling 20-item enumeration that reads as a dump rather than a structured summary. The closing sentences ('Use it to...' and 'Free.') are efficient; the facet list could be trimmed substantially without losing selection value.

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 30 parameters, no required params, and no output schema, the description bears real weight for explaining what comes back, and it does list the returned dimensions including access state and remaining leads. That is enough for an agent to decide when to call it, though it omits whether the response is nested per facet and how the uid/view parameters interact with the counts.

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 73%, so the schema carries most of the burden and baseline is 3. The description's facet enumeration loosely mirrors the parameter list and confirms that values like proven/for_hire/has_rates and rate fields exist as filter dimensions, but it adds no syntax, ranges, or semantics beyond what the schema already documents. Several parameters (uid, bearer_token, added_within_days, max_followers) get no mention at all.

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+resource: it shows what the UGC Database holds for a set of filters, and it enumerates exactly what is counted (niche, country, tier, platform, rates, access). It also distinguishes itself from the search and unlock siblings by framing itself as the pre-flight step ('size an audience before searching or unlocking'). An agent can tell this apart from search_ugc_database and unlock_ugc_database_creators 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?

Explicit when-to-use: 'to pick valid filter values and to size an audience before searching or unlocking.' The alternatives are referenced by function rather than by tool name, so the agent must map 'searching' to search_ugc_database itself. 'Free' adds a strong contrast to the costly unlock path.

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