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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false. The description adds genuinely non-redundant context: that persisting configuration does not trigger a call (the main behavioral ambiguity for a telephony assistant) and that the response carries revision, configuration, and attached resource identifiers. It omits auth requirements and failure behavior.

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?

Three short sentences, front-loaded with the action and immediately followed by the most decision-relevant caveat. The only inefficiency is that 'Saving configuration does not place a call' is duplicated verbatim inside the schema's data 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?

With no output schema, the description does helpfully sketch the return payload, and it covers the key side-effect question. However, for a nested-object create tool it leaves gaps around required-for-functioning fields, pipeline_mode defaults, and error conditions, so it is adequate but not complete.

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%, with every nested field of the single 'data' parameter documented, so the schema carries the parameter burden. The description adds nothing about individual fields such as pipeline_mode's realtime/cascading tradeoff or which fields are needed for a usable assistant, so the baseline 3 applies.

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 with a specific verb and resource ('Create a assistant'), which cleanly distinguishes it from get_assistant, update_assistant, and delete_assistant in the sibling list. It stops short of naming any sibling or scope condition, so the differentiation comes from the name alone.

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?

There is no guidance on when to create versus update, no mention of prerequisites (e.g., that model/voice need to be chosen from a supported set), and no note on what to do if an assistant with the same name exists. 'Saving configuration does not place a call' clarifies side effects rather than usage selection.

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