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

Beyond the readOnlyHint and idempotentHint annotations, the description adds meaningful behavioral context: the tool is free, requires no API key, accepts any valid X-Agent-Identity token, and returns tier='anonymous' for keyless callers with anonymous limits. It also discloses cost and latency, giving the agent a fuller operational picture.

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?

Although longer than average, every section earns its place: clear function summary, motivating example queries, explicit usage guidance, and cost/latency notes. The information is front-loaded and organized, with no redundant filler.

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 compensates by listing the exact return fields and reset behavior. It also covers authentication edge cases, cost, latency, and usage frequency, making it complete for an agent to decide when and how to invoke the tool.

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?

The input schema has zero parameters, so there is no semantic ambiguity to resolve. The description reinforces the empty call shape with check_quota({}) examples, matching the baseline of 4 for parameterless tools.

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: 'Returns the caller's current quota state', and enumerates the exact fields returned (operations used, remaining, daily limit, tier, reset time). This clearly differentiates it from siblings like check_compliance and get_status.

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?

Provides explicit WHEN TO USE and WHEN NOT TO USE sections, including when to call proactively and after a rate_limited error. It also tells the agent not to call on every invocation because quota is already injected into write-tool responses, which serves as an alternative source of the information.

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