Research a Bilibili Video

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

The readOnlyHint annotation already declares the operation safe, and the description adds meaningful behavior: it samples at most 20 root comments but presents only 3-5 representative ones, and it clarifies channel handling per mode. This goes beyond the annotation without contradicting it.

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?

The description is two sentences long, front-loaded with the core action, and contains no filler. Every clause earns its place, covering resolution, metadata, comment sampling, and research modes efficiently.

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?

The description covers the main workflow (resolve, attach metadata, sample comments, modes) well for a read-only analysis tool. It lacks details on output format or error handling, but given the absence of an output schema, this is a minor gap.

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 each parameter is already well-documented. The description adds a bit of context about comment sampling and modes, but it does not significantly enhance understanding beyond the schema fields.

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 clearly states a specific verb+resource: 'Resolves a public Bilibili URL' and 'attaches public metadata', which distinguishes it from generic tools like analyze_video. It also specifies scope (Bilibili) and modes (language-only, visual-only, multimodal), making its purpose unambiguous.

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?

The description implies usage for public Bilibili videos through the URL mention, and the modes provide context for when to use each variant. However, it does not explicitly state when to choose this tool over siblings (analyze_video, inspect_video_window) or any exclusions.

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