add_text_overlay

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

With no annotations, the description carries the full burden of behavioral disclosure. It does disclose two key behaviors: the text is 'burned' onto the video (irreversible) and can be time-limited. However, it does not mention permissions, whether the input file is modified, or the output format, which would be valuable.

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 description is a single, efficient sentence that front-loads the core action. No wasted words; every element (burn text, optional time range) adds value.

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?

Given the tool's 8 parameters, lack of output schema, and no annotations, the description is too sparse. It does not explain what the output is (e.g., the output_path), whether the original video is changed, or any prerequisites or side effects. The time-range functionality is mentioned but not expanded upon.

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?

The schema already covers 63% of parameters with descriptions (input/output paths, start/end times, font color). The tool description only reiterates the text and time range, adding no new parameter semantics. This is acceptable given the moderate schema coverage, but the description could have reinforced key parameter relationships.

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 clearly states the action ('Burn text') and the target resource ('onto a video'), with examples ('caption or title') that make the purpose unambiguous. It distinguishes itself from sibling tools like add_watermark by focusing specifically on text overlays.

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?

The description implies usage through examples (caption/title) and the time-range option, but it does not explicitly state when to use this tool versus alternatives like add_watermark or add_fade. There are no exclusions or alternative names mentioned, so guidance is only implicit.

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