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

Goes well beyond the annotations (readOnlyHint=false, openWorldHint=true): it discloses that calling spends the creator's video minutes, that a creator without minutes instead gets one free 10-second preview, a 10-per-day rate limit, and an auth requirement. That is exactly the cost/authorization context an agent needs before invoking a non-idempotent, open-world mutation.

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?

Six dense sentences with the core purpose front-loaded, followed by prerequisites, cost behavior, limits, and auth. No filler and no repetition of schema-declared enums, default values, or annotation flags.

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 six-parameter, cost-incurring generation tool, the description covers purpose, prerequisites, async polling pattern, rate limits, and authorization. An output schema exists, yet it still adds the useful 'returns a video id' pointer, so nothing material 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?

Schema coverage is 100%, so baseline is 3, but the description adds real meaning beyond the schema: the script is the spoken narration only and should be 110-2700 words (a constraint absent from the schema's maxLength/minLength). Other parameters (tone, voice, character_id) are already well documented by the schema, so it earns a 4 rather than a 5.

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: turning a script into a hand-drawn Alpy video with AI narration. It also names the upstream (write_youtube_script) and downstream (get_video) siblings, but never explains how it differs from the closely-named make_full_video sibling, leaving one differentiation gap.

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?

Explicit workflow guidance: write the script first with write_youtube_script, confirm the creator authorizes spending minutes before calling, then poll get_video every minute. Prerequisites (connected Alpy account or API key) and the daily cap of 10 are stated outright, so an agent knows exactly when this call is appropriate.

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