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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds 'live' freshness and 'used/remaining' content, but omits units, rate limits, and authentication requirements.

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?

One compact phrase with zero waste, front-loading the metric. It is a sentence fragment rather than a full sentence, but there is no padding.

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 read operation with one documented parameter and annotations covering the safety profile, the description conveys the return concept adequately. No output schema is needed, though a hint about return format would be a minor improvement.

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% and the single proxy_id parameter is documented. The description's 'for one proxy' aligns with the schema but adds no syntax, format, or validation detail beyond it.

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 the resource and scope (traffic for one proxy) and the metric (used/remaining), so an agent knows what it returns. However, it does not name a retrieval verb or differentiate from siblings like get_account or list_proxies.

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?

No indication of when to prefer this over list_proxies or get_account, nor prerequisites such as proxy ownership. Usage is only implied by the tool name and the phrase 'for one proxy'.

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