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

With only readOnlyHint=false available, the description carries the load and does so well: it discloses that this is a mutating partial update and that changing aspect letterboxes existing footage rather than re-cropping. That is a genuinely non-obvious side effect an agent would otherwise get wrong. It does not mention permissions, validation failures, or whether existing captions are re-rendered under a new preset.

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?

Three short sentences, each earning its place: what it sets, how partial updates work, and the one behavioural gotcha. Front-loaded with the resource and field list, no filler.

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 mutation tool with no output schema, the description covers scope, partial semantics and the main surprising side effect. Remaining gaps are minor: no statement about what is returned or whether invalid combinations are rejected.

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 50% - fps, project_id and background_color are documented in the schema, while aspect, resolution and caption_preset rely on their enums alone. The description adds real meaning for aspect (letterbox vs. crop) but gives nothing on valid fps values, resolution tiers, or caption preset differences, so it only partially compensates.

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?

Names a specific verb and resource (project output settings) and enumerates the exact fields it controls: aspect ratio, resolution, frame rate, background colour, caption style. This clearly separates it from siblings like studio.update_scene or studio.reframe_scene, which edit content rather than project-level output config.

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 states partial-update semantics ('every field is optional - only what you pass changes') and redirects the agent to scene reframing when framing, not letterboxing, is wanted. It doesn't name the exact sibling tool (studio.reframe_scene), so it stops just short of a full when/when-not routing rule.

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