add_text

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

With no annotations, the description carries the full behavioral burden and discloses very little: no indication of whether the call returns an overlay id needed for later update_text/remove_text, no statement about overlapping text or default styling behavior. It does contribute the useful fact that font_size is normalized to a 1080p canvas and that \n creates line breaks, which is real added context.

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 front-loaded sentences with no padding, and the parameter hints are appended where an agent will look. It is efficient, though the terseness contributes to the coverage gaps noted above.

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 an 8-parameter mutation tool with no annotations, no output schema, and no per-parameter schema descriptions, the description is far from complete. An agent still cannot tell the units of start/end, what the return value is, or how this relates to update_text/remove_text.

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 0% across 8 parameters, so the description must compensate and largely does not. It clarifies font_size scaling and newline handling in text, but leaves project, start, end, color, box, and the position enum (top/center/bottom/lower-third) unexplained, including whether start/end are seconds or frames.

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 ('Add a text overlay') plus the scope ('at timeline times'), so an agent knows exactly what the tool produces. It does not distinguish itself from siblings like update_text or remove_text, so it stops 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?

Nothing says when to use this versus update_text (modifying existing overlay) or remove_text. The phrase 'at timeline times' hints at placing new timed overlays, but there is no explicit when/when-not guidance and no mention of prerequisites such as the project already existing.

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