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

Annotations already declare readOnlyHint and idempotentHint, so the base safety profile is known. The description adds useful behavioral context beyond that: results are scoped to the user's Switch account, costs are rough per-second estimates rather than exact quotes, and model constraints like aspect ratios and durations are included.

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 purposeful sentences. The first sentence front-loads the main purpose and return contents, the second gives direct usage context, and the third routes to an alternative. No filler or redundant restatement of the title.

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 no-argument, read-only list tool with no output schema, the description is complete: it states what will be returned, when to use it, when not to use it, and which sibling tool handles the adjacent exact-quote case. Nothing an agent needs to decide whether to call it is missing.

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?

The tool has zero parameters)Skip, so the input schema carries no burden. With 0 params the baseline is 4; the description appropriately focuses on output content and usage context rather than parameter details.

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 opens with a specific verb and resource: 'List the video providers, models, and modes available to your Switch account'. It then enumerates the exact returned details (required inputs, aspect ratios, durations, rough per-second cost), which makes the tool's purpose unmistakable and separates it from quote_video.

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 gives explicit when-to-use guidance: 'Use this when the selected model or its required inputs are unknown.' It also provides a clear exclusion ('Keep a known selected model; do not run model searches for an ideas question') and names an alternative for exact quotes ('Use quote_video for a current exact token quote').

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