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

Annotations only indicate this is not read-only, not idempotent, and not destructive. The description adds substantial behavioral context: it validates first, creates a public guest scene with QR when no key is provided, persists the scene after signup/Remix, and enforces account limits for keyed saves. This goes far beyond what annotations convey.

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 dense but efficient: three sentences front-load the primary outcome, then validation, then guest-versus-key behavior. Every clause carries operational information, and there is no filler or repetition 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 creation tool with no output schema and minimal annotations, the description is remarkably complete. It covers the return value (editor URL), the validation step, guest persistence and QR behavior, account behavior with limits, and the role of signing up/remixing. An agent has enough context to invoke it correctly and set expectations.

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 description coverage is 100%, and the schema already documents all three parameters: name default, scene format with a pointer to get_scene_format, and make_public sharing behavior. The description adds no parameter-specific detail, so the baseline of 3 applies.

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 states a specific verb and outcome: 'Save a scene and get an editor URL where it opens in the visual editor.' This clearly distinguishes create_scene from siblings like validate_scene or update_scene by emphasizing creation plus the editor-URL result.

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 clear usage conditions around authentication: works without a key as a public 24-hour guest scene, or with a key saving to an account with limits. It does not explicitly say 'use update_scene for existing scenes' or 'use validate_scene if you only want validation,' so it stops short of full alternative routing.

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