get_metadata

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

No annotations, so the description carries the load and does disclose a real behavioral trap: for multi-part videos (n_pages > 1) downstream tools read only part 1 unless page= is passed explicitly. It doesn't mention batch-size limits, failure modes for invalid BV ids, or rate/cost constraints, which keeps it short of a 5.

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-loaded with the core purpose, then warnings, then field semantics — good ordering. Some internal jargon ("批次 C3 放回来的", "最便宜的一手形态信息") is noise, and emoji-heavy emphasis inflates length slightly, but no sentence is purely redundant.

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?

Output schema exists, yet the description still usefully explains the most consequential return fields (n_pages vs pages, per-page cid). Combined with the usage routing, an agent has what it needs; only batch-size/error behavior 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 coverage is 0% for the single required 'bvids' parameter, and the description only indirectly reveals it takes BV ids ("你只有一个 BV 号"). It adds no detail on array size limits, ID format, or whether non-BV ids are accepted, leaving a real gap for the only 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?

Starts with a specific verb+resource: batch-fetch complete metadata (cid/pages, tags, full description). It explicitly contrasts itself with the broad-scan path (search results already carry metadata), so an agent can distinguish it from search_videos/scan_topic without reading schemas.

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 an explicit when-not (broad scanning doesn't need it) followed by two enumerated when-to-use conditions: you have only a BV id, or you need a cid — and it even notes that get_transcript/get_danmaku handle cid internally. That is the strongest form of routing guidance.

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