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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false. The description adds value beyond that by explicitly stating 'Offline data, no network calls' and the empty-filter behavior ('empty filters return every row'), which is useful operational context an agent would otherwise have to infer.

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-loads the purpose in the first clause, then the usage cue and the offline/empty-filter behavior. The platform and field enumeration is dense but earns its place by scoping what data the tool returns.

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?

There is no output schema, yet the description describes the returned row contents (spec fields plus official source links and recent changes), the offline nature, and filter fallback behavior. Combined with 100%-covered parameters, an agent has everything needed to call and interpret this tool.

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 100%, so both the format and platform filters are already fully documented with substring semantics and empty-value behavior. The description adds no filter syntax or format detail beyond the schema, so it sits at the baseline.

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 ('look up 2026 upload specs') and enumerates exactly what is returned (aspect ratio, resolution, length, file size, caption/hashtag limits). This is clearly distinguishable from siblings like get_video_info or transcribe_video, which operate on actual videos rather than reference specs.

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 context: 'Use it before exporting or cropping a video for a platform.' It doesn't name an alternative tool or state when not to use it, but no sibling covers the same reference-data job, so the guidance is clear and actionable.

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