resolve_douyin_url

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

With no annotations, the description fully carries behavioral disclosure. It explicitly states limitations: does not save media, does not expose signed stream URLs, and challenges are reported but not bypassed. This is transparent, though it could mention if any authentication or rate limits apply.

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 extremely concise: two sentences no wasted words. The first sentence states purpose and constraints, the second explains modes. It is front-loaded with the most critical 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?

Given the tool has an output schema, return values need not be described. The description covers purpose, behavior, and mode guidance. It might be missing potential error scenarios or prerequisites, but overall it is sufficiently complete for a URL resolution 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 coverage is 0%, so the description must compensate. The description explains the url parameter implicitly (the share URL) and thoroughly describes browser_mode options ('auto', 'direct', 'browser') with their behaviors, adding meaning beyond the schema's defaults.

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 the tool resolves a Douyin share URL without saving media or exposing signed stream URLs. It uses a specific verb ('resolve') and resource ('Douyin share URL'), and distinguishes from siblings like download_douyin_media (saves media) and probe_media (likely probes, not resolves).

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 provides clear guidance on using browser_mode: 'auto' normally, 'direct' for redirect expansion, 'browser' for Playwright observation. It mentions human verification challenges are reported but not bypassed, implying when not to expect full resolution. However, it does not explicitly state when to use alternative tools like download_douyin_media.

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