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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description does add real context beyond that: per-duration credit pricing (including Premium/realistic-model tiers), required inputs per format, what each outputs, and that it returns hook formulas usable as 'hook' on studio_generate plus org avatars. That is solid added value, but it stops short of operational traits like response size or latency for an enumeration endpoint; a 3 is fair with annotations carrying safety.

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 purpose, then returns, then the call sequence. The long parenthetical format enumeration is slightly dense but each item conveys a distinct capability the agent may need to match against a user request, so the length is largely earned.

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?

The tool is a zero-required-input listing call with an output schema, and the description already summarizes the return payload (formats with prices, inputs, outputs, hook formulas, avatars) plus the required downstream workflow. Nothing an agent needs to call it 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?

There is a single optional parameter ('reasoning') and schema description coverage is 100%, so the schema fully documents it. The description correctly implies the tool is callable with no meaningful input. Baseline 4 applies since the description adds no contradicting or missing parameter meaning.

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?

Specific verb ('List everything Studio can generate') plus a concrete enumeration of the resource: post formats, slideshows, UGC talking heads, stories, hook+demo videos, voiceovers, images, clips, avatars. It is clearly distinct from sibling studio_generate (which produces) and studio_recipes.

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 sequencing: 'Call this before studio_generate, tell the user the price in credits, and get their confirmation before generating.' It names the alternative tool and the prerequisite workflow, leaving nothing to inference.

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