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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful behavioral context: it frames the tool as 'Switch Vision — watch and understand like a human', describes what it extracts (tone, mood, structure), and clarifies that 'Switch resolves its own links' internally. It doesn't discuss rate limits or latency, but with annotations covering safety, this is strong.

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 three sentences, front-loaded with the core purpose, followed by input specifics and usage context. Every sentence earns its place: no filler, examples are embedded naturally, and the structure flows from what to how to when.

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 2-parameter tool with no output schema, the description covers all necessary context: accepted input types, optional question, use case, and a hint at the output ('answer a question about it'). It even mentions the tool works on images as well as videos, which is a useful scope clarification not obvious from the schema.

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%, but the description adds significant meaning beyond the schema. It expands video_url to include 'public https video URL, including YouTube' and specifies Switch video/asset IDs from list_my_videos / list_my_assets / upload_media. It also gives concrete question examples, enriching the semantics of both parameters beyond the schema's basic descriptions.

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 states a specific verb+resource: 'watch and understand a video (or image) like a human and answer a question about it'. It enumerates the analysis dimensions (scenes, subjects, actions, on-screen text, pacing, mood, sentiment), which clearly distinguishes it from siblings like video_to_prompt or analyze_video_report. This is a clear, specific purpose.

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 explicitly tells when to use the tool: 'Use this whenever the user gives you a reference video and wants its style, energy, structure or content understood — for example before making a new video that matches it.' It also explains the two input modes (public URL vs Switch video/asset ID), providing clear context for selection against alternatives.

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