add_overlay

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

No annotations are provided, so the description carries the full behavioral burden. It says the tool places an image over a video, but does not clarify whether the source is modified or a new file is created, overwrite behavior, permission requirements, encoding implications, or return behavior.

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 front-loaded sentence with no wasted clauses. It efficiently states the capability and the main customizable dimensions.

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?

The schema is rich and fully documented, and outputPath conveys destination behavior. However, with no annotations and no output schema, the description should say more about the result of the operation, such as whether it returns the output path, how existing files are handled, or what hardwareAcceleration changes.

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 100%, so all eight parameters are already documented with meaning, defaults, ranges, and format expectations. The description repeats position, padding, scaling, and opacity at a high level without adding syntax or constraints beyond 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 names a specific action (place an overlay) and specific resource types (watermark, logo PNG, branding graphic) over a video. It is clear enough to distinguish this from subtitle or audio tools, but it does not explicitly contrast itself with siblings such as burn_subtitles or create_split_screen.

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 a branding/watermarking use case, but gives no explicit when-to-use guidance, prerequisites, or alternatives. It does not say when to choose add_overlay instead of related tools such as burn_subtitles or create_split_screen.

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