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

Annotations cover the safety profile (readOnly=false, idempotent=false, openWorld=true, destructive=false), and the description adds value beyond them: credit charging tied to script length, audio upload to Spaces with a signed URL and 24h TTL. It does not state failure modes, rate limits, or what happens when the character limit is exceeded, so it falls short of a 5.

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-loads what the tool does, then when to use it, then exclusions, then parameter hints — a sensible order with no filler sentences. Slightly redundant since the voice-selection sentence duplicates the voiceId schema description, but nothing is wasted at the sentence level.

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?

An output schema exists, so return values need no prose, yet the description still flags the signed URL and its TTL. Combined with cost behavior, scope, and the non-realtime exclusion, an agent has everything needed to select and invoke this tool correctly.

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 the baseline is 3. The description restates voiceId behavior (pass an id or omit for the default narrator) and the free-form nature of text, but adds no syntax, format, or limits beyond what the schema already declares, including the 5000-char cap and the no-op 'description' param.

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+resource ("Generates a voiceover from text") and names the underlying engine (Paradise Modern, Qwen3-TTS), which an agent could not infer from the name alone. It also distinguishes itself from the sibling quote_voiceover and from real-time conversational TTS, so the agent can route correctly without opening a schema.

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?

Gives concrete when-to-use cases (demo-video narration, tutorial audio, one-shot batch TTS), an explicit when-NOT ("NOT a real-time conversational voice"), and names the alternative tool for cost preview ("use quote_voiceover for a preview"). Both the alternative and the selecting condition are stated, not implied.

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