bili_subtitle

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

With no annotations, the description carries the burden and does disclose meaningful traits: whole-text return, exclusion of timestamps/frames/ASR, and the failure mode that missing subtitles stay missing rather than being synthesized. It omits auth/cookie requirements, which matter for Bilibili subtitle access, but the output schema covers return shape.

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?

Three short sentences, front-loaded with what is returned, followed by exclusions and the failure caveat. No filler; every clause carries information.

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?

For a one-parameter read tool with an output schema and no annotations, the description covers output scope, exclusions, and the missing-subtitle case. Only auth prerequisites and the exact meaning of "first-P" for multi-part videos remain unaddressed.

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 bvid parameter and the description never mentions it, but "first-P" implicitly conveys that no part/page selector is needed — bvid alone targets the first part. That is real added meaning beyond the bare string property, though format expectations remain undocumented.

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 ("Read ... subtitle ... FULL text") and scopes it to the first part only. "No timestamps/frames/ASR" implicitly separates it from transcript or danmaku-style tools, but no sibling is named explicitly.

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?

Usage is only implied: it reads existing subtitles and explicitly will not generate/transcribe them, so an agent knows not to expect ASR fallback. No alternative sibling (e.g. bili_video_info, bili_danmaku) is named for cases where subtitles are absent.

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