change_voice

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

Annotations mark it non-read-only but non-destructive and open-world; the description adds genuinely new behavioral facts by naming the concrete outputs (generated/<file>-<voice>-vN.wav plus an .mp4 when video is present), which reassures the agent that originals are not overwritten. It also implies the ElevenLabs account dependency. It does not say whether the render is synchronous or must be polled via run_job/get_job.

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?

Front-loaded with the core action, then scope, then outputs — a sensible ordering. It is dense but every clause carries information; only the slightly colloquial 'Say a clip again' opening costs it a point.

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 output schema, the description covers the operation, the duration cap, the voice source and the produced artifacts. The notable remaining gap is execution behavior — whether this returns immediately or produces a job that must be polled through the sibling run_job/get_job.

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 100%, so the baseline is 3, but the description adds a real constraint absent from the schema: start/end selection is capped at 5 minutes. It also frames file vs session as alternative sources and clarifies that voice comes from the ElevenLabs account, adding meaning beyond the field blurbs.

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: re-perform a recorded clip in a different voice via the ElevenLabs voice changer, preserving words, timing and emotion. That is far more informative than the bare name and implicitly separates it from text-to-speech siblings like voiceover, though no sibling is named explicitly.

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?

Usage is implied rather than stated: 'The user acts the line, a character voice comes out' tells the agent this operates on already-recorded audio, and 'whole file or start/end' hints at scope choices. There is no explicit when-not or pointer to an alternative tool (e.g. voiceover for synthesizing new speech), so the agent must infer the routing.

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