add_text_captions

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

With no annotations, the description carries the full burden, and it delivers the key non-obvious behavior: cues are rasterized into graphics clips on the timeline rather than editable caption objects. It leaves out mutation side-effects (e.g., where clips land, whether existing captions are replaced) and permission/prerequisite notes, which keeps it below a 5.

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?

Two sentences, zero filler, with the core purpose front-loaded and the sibling disambiguation after it. Nothing repeated from the schema or the tool name.

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 15-parameter, no-annotation, no-output-schema tool, the description covers what it produces and when to prefer an alternative, but says nothing about the required captions array shape, whether styling is global across cues, or what the call returns. Adequate to pick the tool, thin on invocation detail beyond the schema.

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 ~80%, with descriptions on most styling params (font, color, shadow, fontSize, maxWidth, position, trackIndex defaults), so the schema already does the heavy lifting. The description adds no parameter-level meaning such as whether styling applies to all cues or how x/y interact with position beyond what the schema states.

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 ('Burned-in styled captions as graphics clips') and clarifies the output form ('each cue becomes a text image on the timeline'), which distinguishes it from add_captions and add_text in the sibling list without the agent needing to open 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 names the alternative (add_captions) and the condition that selects it ('when you want editable Premiere captions'), giving a clear this-vs-that routing rule. The 'burned-in / TikTok-Reels style' framing also implicitly scopes it to stylized social captions.

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