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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds real behavioral context beyond that: the cost figure is explicitly a 'rough per-second cost' rather than an authoritative quote, and the exact-quote path is delegated to quote_video. It stops short of noting caching, pagination, or account-scope limits, so not a full 5.

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?

Four short sentences, front-loaded with the what before the when, and each sentence carries distinct information (payload, trigger, anti-trigger, alternative). Slightly dense in the field list and the phrase 'an ideas question' is loose, but nothing is redundant.

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?

With no parameters, no output schema, and annotations already covering the read-only safety profile, the description supplies everything an agent needs: what comes back, when to call it, when not to, and which sibling to use instead for exact pricing.

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 takes zero parameters, so there is nothing for the description to disambiguate and the schema imposes no burden. The description's enumeration of returned fields is the only relevant semantic content, and it is sufficient for a parameterless listing call.

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?

States a specific verb and resource ('List the video providers, models, and modes') plus the exact payload (required inputs, aspect ratios, durations, rough per-second cost). This clearly separates it from siblings like explore_models, list_upscalers, and quote_video without needing to open any schema.

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?

Gives an explicit trigger ('Use this when the selected model or its required inputs are unknown'), an explicit anti-trigger ('Keep a known selected model; do not run model searches for an ideas question'), and names the alternative for the adjacent need ('Use quote_video for a current exact token quote'). Routing between tools is fully determined.

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