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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description reinforces this while adding genuinely new context: what is rendered versus omitted (no lighting/materials), optional label overlays, per-project-type framing behavior, and that it 'never counts as an export'. This is behavior an agent could not infer from the annotations alone.

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 core purpose is front-loaded in the first clause, and the workflow/alternative guidance follows. The prose is dense and mostly earns its place, though the checklist enumeration and per-type rules make it longer than strictly necessary.

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?

Despite no output schema, the description states what comes back ('the sketch image and a short summary'), covers the workflow and the sibling alternative, and explains the non-obvious framing semantics for films, launch videos, and store sets. 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?

Schema coverage is 100%, so the baseline is 3. The description nonetheless adds meaning beyond the schema by tying parameters to project types: `frames`/`time` apply to films and launch videos, launch videos default to the key moment of every block, and store sets use `language` and lay images side by side.

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 ('renders a fast schematic sketch of a project') and immediately scopes it against siblings by contrasting with export_image. An agent can distinguish it from export_image without opening either 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?

Explicitly prescribes when to use it ('after every create_project or edit_scene'), what to do with the result ('inspect the image critically against the checklist... then fix what you find'), and names the alternative with its condition ('use export_image only for the final rendered image').

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