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

With no annotations, the description carries the behavioral disclosure burden non-trivial: it states the drop has no audio, that it requires a subsequent voice-generation step, and that the return value is the id. It does not cover permissions or idempotency, but for a one-parameter create with a clear empty initial state, the description is substantially transparent.

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, no filler, and the key point ('new empty voicemail drop') is front-loaded. The follow-up guidance and return value earn their place without bloating the description.

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 simple create tool with one optional parameter and no output schema, the description covers all necessary context: what is created, what state it is in, the next step alternatives, and the returned id. Nothing an agent needs to call it successfully is missing.

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 schema fully documents the optional 'name' parameter and its default. The description adds no new parameter semantics beyond what the schema already provides, establishing the baseline score of 3.

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 starts with the specific verb-resource pair 'Create a new empty voicemail drop' and immediately clarifies what state it is in ('no audio yet'), distinguishing it from the follow-up generation tool. It also names the return value ('Returns the new drop's id'), leaving no ambiguity about the operation.

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?

The description explicitly says to follow up with voicemail_drops_generate_emma to add Felicia's voice, or to have the user record by phone, which tells an agent exactly when and how to use this tool versus the obvious alternative. This is direct routing guidance rather than silent implication.

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