Residential traffic usage by day

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful context beyond that: the metric it does not return (remaining quota), where that value lives, and how the two combine for a burn-rate estimate. It stops short of describing the return shape or cost/latency traits.

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 tight sentences, front-loaded with the purpose, then the use case, then the critical gap and its fix. No repetition of the title or schema, and every sentence carries routing or constraint information.

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 should ideally sketch the return (units, per-day granularity, empty-case behavior); it gives granularity only via the title. It does, however, close the biggest completeness risk for this tool by pointing to where the complementary remaining-quota value lives and how to combine them.

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% – 'days' and 'proxy_id' are both documented in-schema with bounds and defaults. The description implies a daily time series but adds no format, timezone, or unit detail beyond the schema, so 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?

States a specific verb and resource (daily traffic consumption for a residential proxy) and explicitly delimits scope against list_proxies by noting the remaining quota is NOT returned here. An agent can distinguish it from the sibling usage/quota tools without opening either schema.

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?

Gives the concrete question it answers ("how much have I used / how long will the bundle last"), names the alternative source for the missing data (list_proxies → residential_traffic_left_mb), and states the intended workflow of combining both before add_residential_traffic. Explicit when and which sibling to pair with.

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