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

Annotations already declare readOnly/idempotent/openWorld, so the safety profile is covered. The description adds substantive context they cannot: the notes field carries expiry, instant-serve durations, and trial status that 'silently changes what the library returns,' plus the 403 consequence of guessing.

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?

Front-loaded with the core statement and the CALL THIS FIRST imperative, then supporting detail. Slightly verbose with the quoted question list, but every clause carries actionable 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?

Output schema exists, so return values needn't be enumerated, yet the description still adds value by flagging the notes field's hidden behaviors. Nothing an agent needs to invoke this correctly 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?

Zero parameters, so per the rubric the baseline is 4. The description has no parameters to explain and adds no misleading parameter semantics.

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 resource — license capabilities and remaining quota — with a clear read verb implied by the title. An agent immediately understands this is the entitlement/quota lookup, distinct from the generate_* and list_* siblings.

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?

Explicitly says 'CALL THIS FIRST, before generating anything,' giving both sequencing and the trigger condition. It also names the concrete decisions it resolves (bitrate/format/mode/intensity, max duration, remaining tracks) and warns that guessing causes a wasted call and a 403.

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