Add segment

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

Annotations already declare this is not read-only and not destructive, so safety is largely covered. The description adds genuinely new behavioral context beyond them: LosslessCut replaces the initial full-length segment rather than appending alongside it, and repeated calls accumulate parts. It does not say what is returned or whether new segments are appended or inserted.

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 core action, then the special-case rule, then the multi-call pattern. Nothing is redundant or padded.

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 two-parameter mutation tool with annotations and no output schema, the description covers the essential action and the one non-obvious side effect. The remaining gap is the relationship to sibling segment tools (set_segments, select_segments), which the agent must work out on its own.

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 description only repeats the parameter names ("from start to end") and adds no information about units, accepted timecode formats, or whether start/end are inclusive. With schema description coverage reported at 0%, the description would need to carry the format and unit semantics and does not.

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 verb and resource ("Adds a new segment") and defines its bounds ("from start to end"). It also implicitly distinguishes itself from a bulk setter by noting it should be called repeatedly for multiple parts, though it never names set_segments or select_segments directly.

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?

It gives concrete usage context: call it once to define the cut, call it several times to cut out several parts. That is a real when-to-use signal. It stops short of explicit exclusions, such as when to prefer set_segments or set_cut_points instead, so the agent must infer the boundary.

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