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

With no annotations, the description carries the full behavioral burden, and it only discloses that execution is synchronous. It says nothing about permissions, whether applying overwrites existing captions, whether modes like "clear" or "recreate" are destructive, or what happens on failure.

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?

A single sentence with no filler; the synchronous constraint and the autonomous_edit contrast are both front-loaded.

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 mutation tool with six undocumented mode behaviors, an inline nested scene object, and no annotations or output schema, the description is too thin. An agent cannot infer the effect of each mode or how scene and project_id interact.

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 75%, so the baseline is 3. The description adds no information about the mode enum values (add, recreate, style, translate, clear, remove_fillers) or the scene-vs-project_id alternative, leaving important parameter semantics to the schema.

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 resource ("Apply a caption template to a scene") and explicitly distinguishes the operation from the autonomous_edit sibling. It does not clarify what applying a template actually does to the scene, which keeps it short of a 5.

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?

It gives one useful routing signal: use this for synchronous application rather than going through autonomous_edit. However, it offers no guidance on when to choose this over queue_edit or other caption-related siblings, and no conditions for selecting among the mode values.

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