Extract media metadata from a link

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

With no annotations provided, the description carries the burden and it does add useful behavioral context: the ssv_ token expires in 5–15 minutes, and the format parameter's audio mode only yields MP3, requiring an additional call for YouTube/Instagram. It does not state side effects, but 'extract metadata' implicitly signals a read-only operation.

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?

A single, dense sentence that front-loads the supported platforms, the core operation, and the key output details (token expiry and download URLs). Every clause earns its place and there is no filler.

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?

Given the tool's low complexity (2 params, no nested objects) and no output schema, the description adequately explains what is returned. It does not mention how outputs connect to sibling tools like download_media, but the token and URL mentions make the workflow inferable.

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 100% so the baseline is 3, but the description adds meaningful nuance beyond the schema, particularly that audio mode only returns MP3 and that YouTube/Instagram may require a second call. This helps an agent understand format-specific behavior not fully captured by the enum.

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?

Description states a specific action ('提取媒体元数据与可下载格式') on clearly listed resources (TikTok/Instagram/YouTube/Douyin links) and names concrete outputs (ssv_ token and download URLs). This clearly differentiates it from siblings like download_media and get_thumbnail, which perform different actions on the same resource type.

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 says what the tool does but gives no guidance on when to prefer it over download_media or get_thumbnail, and does not mention any exclusions or prerequisites. An agent must infer that extraction precedes download from the token mention; no explicit routing is provided.

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