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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive. The description adds the key behavior of opening the checkout page in the browser when open=true, and clarifies that this is a general status/upgrade info tool. It does not contradict annotations and adds useful context about the optional side effect.

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?

The description is three sentences, front-loaded with the main purpose. Every sentence provides distinct value: what it shows, when to call it, and the key parameter behavior. No fluff or redundancy.

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 tool with 2 optional parameters, full schema coverage, strong annotations, and no output schema, the description is complete. It explains the primary purpose, usage timing, and the optional browser-opening behavior. Nothing essential is missing.

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%, so the baseline is 3. The description does not add any parameter semantics beyond what the schema already provides. It mentions 'open=true' but that is exactly what the schema says. There is no bonus for repeating schema content.

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 'Show' and clearly states the resource (current MisarMail plan, quota usage, and what upgrading unlocks). It distinguishes the tool from siblings by focusing on plan and upgrade context, which is unique among the listed tools.

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 when-to-use guidance: 'Call it any time — not only after hitting a limit.' It does not mention alternatives or exclusions, but for this tool it is clear enough. A 5 would require explicit alternatives or when-not-to-use, so 4 is appropriate.

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