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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description reinforces safety by stating 'Reads only: it never changes the plan or takes payment.' It also clarifies the side effect of open=true on local installs, which goes beyond annotations. That extra behavioral detail is useful, though not extensive.

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 sentences, front-loaded with the core purpose, then usage guidance, then behavioral notes. No wasted words, though slightly more verbose than necessary for a simple read tool.

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?

Given a 2-parameter read-only tool with rich annotations and no output schema, the description covers what the tool shows and its behavioral constraints. The output format is not described, but that's acceptable without an output schema. Complete enough for correct invocation.

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 coverage is 100%, so the schema already fully documents both parameters. The description adds minor context about open=true opening a browser link on local installs, but the plan parameter's default behavior is left to the schema. Baseline 3 is appropriate.

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+resource: shows the MisarMail plan, quota remaining, and upgrade unlockables. Clearly distinguishable from siblings like get_analytics or get_warmup_status, which cover different resources.

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?

Explicitly says 'Call it any time — not only after hitting a limit,' giving clear context for use. No named alternatives or exclusions, but the open-ended guidance is sufficient for a read-only info tool.

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