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

readOnlyHint already declares safety. The description adds valuable context about identity resolution: IP-based for anonymous use and account-based once robot_key is linked, which goes beyond annotations.

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?

Single, dense sentence front-loads the primary output (price and free minutes) and the identity condition. No wasted words.

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?

Given annotations cover safety and schema covers parameters, the description completes the call context by explaining the robot_key identity behavior. Output schema is absent, but return values (price, free minutes) are clear from the description.

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 coverage is 100%, so parameter syntax is fully documented. The description adds semantic nuance about robot_key linking and identifies the identity scope, going slightly beyond the schema's description.

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 states a specific verb (pricing/estimate) and resource (transcription cost and remaining free minutes), clearly distinguishing it from siblings like start_transcription or get_service_info.

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 implies usage for estimating cost before transcribing and clarifies the identity resolution (IP vs. linked user) via robot_key, but does not explicitly say when to use it versus checking service info.

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