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), and the description still adds meaningful behavior: the exact thresholds that determine inclusion, the expectation that an empty result is normal rather than a failure, and that the tool is free to call. This is context the agent could not derive from annotations or schema.

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?

It is front-loaded with the usage trigger, then the definition, then exclusions, and every sentence carries information. Minor redundancy: 'Free and read only' restates readOnlyHint from annotations, and the three quoted user phrases are somewhat repetitive, though they do aid intent matching.

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?

An output schema exists, so return formatting need not be described; the description only notes 'with the numbers,' which is sufficient. For a zero-parameter, read-only query tool, nothing an agent needs to select or call it correctly 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?

The tool takes zero parameters and the description explicitly says so, which fully aligns with the empty input schema. With no parameters there is no semantic gap to close, and the statement removes any temptation for the agent to invent filter arguments.

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 operation with full scope: it lists posts under 48 hours old with at least 100 views and at least 2x the user's baseline views at the same age. It also anchors the concept to a concrete artifact ('the rule behind the Taking off badge in RipClip'), so the agent knows exactly what is being computed rather than a vague 'performance' query.

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?

It gives explicit when-to-use triggers with quoted user phrasings ('is anything taking off', 'did my last clip pop', 'is my TikTok going viral') and an explicit exclusion list naming three siblings (weekly_report, get_post_stats, why_it_worked) with their distinct purposes. It even pre-empts a likely misinterpretation by stating 'An empty list is a normal answer.'

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