Transcribe a WhatsApp voice message

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

Annotations already mark the tool as read-only, idempotent, and non-destructive, and the description adds substantial behavioral context beyond that: caching, subsequent display of the transcript as [voice message · 0:42], searchability via search_messages, provider-dependent pricing and data handling, the 10-call-per-minute cap, and the TRANSCRIBE_UNAVAILABLE error with explicit do-not-retry guidance.

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?

The description is front-loaded with the core purpose and follows with dense, useful operational facts. Every sentence earns its place: caching, side effects on messages, searchability, cost, rate limits, and the error case. It is detailed but not bloated.

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 tool with no output schema, the description gives enough information about the returned behavior (text), plus caching, upstream and API side effects, when results appear in other tools, and how to handle failure. An agent has what it needs to call this correctly and reason about outcomes.

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%, and the schema already explains message_id and language. The description reinforces that calling with the same message is useful because of caching, but it does not add substantive parameter-level meaning beyond the schema, 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?

The description opens by stating a specific verb and resource: turning a voice note or audio message into text. It also explains the post-transcription behavior in read and search tools, which clearly distinguishes this from siblings like download_media or send_message.

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 makes the intended use clear: transcribe voice/audio messages into text. It also provides strong cost, caching, rate-limit, and error-retry guidance. It does not explicitly name alternative tools or conditions that would rule this tool out, but the context is clear enough for selection.

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