burn_captions

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

No annotations are supplied, so the description must carry the full behavioral burden. It usefully discloses that the burn is hardcoded and always visible, which tells the agent the result is not a toggleable track, but it says nothing about re-encoding/quality loss, output overwrite behavior, or what happens when the subtitle path is invalid or mismatched.

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?

Three short sentences, front-loaded with the operation and scope, with zero filler. The style sentence is somewhat static detail that could be read as implying configurability that no parameter supports.

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 four-parameter media transform with no output schema, the definition covers what the tool does and what subtitle files it eats, but omits the operational facts an agent needs: re-encoding implications, output format/container rules, and failure conditions.

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 50%: input and captions are documented, output reuses the input description via $ref, and font_size has a default and range but no textual meaning. The description's format list reinforces the captions parameter and the style sentence hints at how font_size manifests, but it never explains units or that style is otherwise fixed.

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?

"Burn subtitles into the video (hardcoded, always visible)" names a specific verb and resource and distinguishes the operation from soft-subtitle embedding or the sibling extract_audio/concat tools. It does not explicitly contrast itself with any sibling, which keeps it just 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?

The accepted subtitle formats (.srt, .ass, .vtt) imply the input conditions, but there is no explicit statement of when to use this versus other video tools, no prerequisite notes (e.g., that the source must already carry a subtitle file), and no exclusions.

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