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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, non-destructive, closed-world), and the description adds genuinely new behavior: deduplication to one item per original video, newest-first ordering, and pagination via total/has_more/next_cursor. Repeating 'Read-only' is redundant with the annotations but harmless.

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 and then packs scope, filters, return shape and limits without filler. The density makes it a run-on in places, but no sentence is wasted.

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 the result envelope (total, has_more, next_cursor), per-item fields (ref, content_type, slide_count) and the cross-reference to get_reference_analysis. Nothing needed to invoke or interpret the call 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?

Schema description coverage is 0%, so the description carries the full burden and mostly delivers: q is defined per field (author/title, plus transcript on shared), platform values are enumerated with a scope-specific exception for threads, niche accepts a slug or group, limit is bounded 1-50 with default 10. The cursor parameter is only implied through the returned next_cursor rather than explicitly explained as the pagination input.

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 names a specific verb and resource ('finished ViralDecoder analyses ... the shared library or the account's own analyses') and enumerates the two scopes with their meanings. It stops short of differentiating itself from siblings such as my_library, which appears to overlap with scope=own, so an agent must infer the boundary.

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 opens with an explicit trigger ('Use this when you need finished ... analyses to study or compare') and explains the shared vs own scopes plus which platforms are available in each. There are no explicit exclusions or named alternatives, and the overlap with my_library (scope=own) and find_viral_in_niche is left unaddressed.

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