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

The readOnlyHint annotation already covers the safety profile, so the description does not need to restate it. It does add useful context about plan enforcement and refusal reasons, but it does not disclose additional behavioral traits such as response shape or whether current usage values update dynamically. Given the annotation coverage, this is adequate but not rich.

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?

Two sentences, front-loaded with the core purpose and followed by concrete use cases. Every phrase earns its place, and the description avoids restating the tool name or padding with generic boilerplate.

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 zero-parameter read-only tool with an output schema provided, the description fully covers what the tool does and when to call it. No additional details about parameters or return values are necessary.

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 tool has zero parameters)Skip; the description cannot meaningfully explain parameter meaning beyond the input schema. Per the baseline for zero-parameter tools, a 4 is appropriate because no parameter documentation burden exists.

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 uses a specific verb and resource: "Show your plan, its limits, current usage..." and enumerates exact contents including message-send limits, paired-account limits, and excluded_tools. This distinguishes it from all sibling tools, since none of them claim to expose plan-level quota or refusal reasons.

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 gives explicit invocation contexts: "Call this to see why wa_send_message or wa_pair_account might be refused, how much headroom is left, or why a tool answers plan_required." This is clear usage guidance, though it does not state when not to use it or name alternative tools for the same job.

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