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

Annotations only declare it is a non-read-only, non-destructive, non-open-world operation; the description adds real substance by disclosing the side effects — a pending audio item is filled with the MP3 and word timings are persisted as a transcript, and that it requires an ElevenLabs account voice. It stops short of mentioning generation latency, job/polling behavior, or failure modes when a voice name doesn't resolve.

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?

Two sentences, front-loaded with the core action and its effect, with parameter notes trailing. The `docs` topic reference earns its place as a routing hint, but the backticked voice-parameter restatement duplicates the schema slightly.

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?

With no output schema, the description usefully explains what the call produces (a filled pending audio item plus a stored transcript), and the 11 parameters are fully covered by the schema. Behaviour around the hosted provider — latency, quota, or whether the item appears immediately — is the only notable gap for a mutation tool of this complexity.

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 every one of the 11 parameters is already documented, including the voice id/name default and text audio tags. The description largely restates the `voice` parameter and only adds the pointer to the `docs` `voice` topic, so baseline 3 is appropriate.

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 concrete verb and outcome: narrate text with a hosted ElevenLabs v3 voice and place the resulting audio on the timeline, including that word timings become the media transcript. This clearly separates it from siblings like generate_music, generate_sfx, and generate_image, though those alternatives are never 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 only implied — an agent infers it should call this when it needs spoken narration of a provided text. There is no guidance on when not to use it (e.g. versus uploading existing audio, or search_voices before choosing a voice), aside from a pointer to the `docs` topic `voice` for voice-selection detail.

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