ASL usage and limits

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds meaningful context beyond that: it reads only the *configured* router and data keys (no parameterization, uses ambient credentials) and surfaces limit/quota state, which explains its diagnostic role.

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?

Front-loaded with the primary payload (Smart Router usage), then the secondary one (Data API requests), then a compact usage clause. The first sentence is dense with parenthetical enumerations but every element maps to returned data, so little is wasted.

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 carries the burden of describing returns and does so adequately by listing the usage fields. It stops short of describing the response shape or what happens when a configured key is missing or invalid, which matters given the stated 'check the keys work' use case.

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?

Zero parameters, so the baseline of 4 applies. The description correctly implies the tool is parameterless by referring to 'the configured router key' and 'the configured data key' rather than any caller-supplied identifiers.

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 (get usage/limits) and enumerates exactly what is returned: this month's Smart Router requests used and left, prepaid credits, the key's budget, and Data API requests left today. This clearly distinguishes it from siblings like get_provider_status, get_leaderboard, or get_incidents.

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 two concrete trigger conditions: 'when a tool reports a limit' and 'to check the keys work.' That is clear when-to-use guidance, though it names no alternative tool or a when-not condition, and no sibling overlaps enough to require explicit routing.

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