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

readOnlyHint=true already establishes this as a safe read, so the bar is lower. The description adds that the call is free and that it returns plan tier, limits, and today's alert count, which is genuine behavioral context beyond the annotation, but it says nothing about pagination or rate limits.

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?

A single front-loaded sentence that enumerates the payload, followed by a one-word cost flag. Compact and waste-free, though the 'Free.' fragment is slightly abrupt.

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 usefully names the returned data (plan, limits, alerts today, watches), which is what an agent needs to decide the call is worthwhile. Only missing element is pagination or result-size behavior.

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% and there is a single parameter, so the schema already documents the key fully; the description's 'for a key' adds no syntax or format detail. Baseline 3 is appropriate when the schema does the work.

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 (Show) and enumerates the resources returned: plan, limits, alerts today, and all watches for a key. It clearly contrasts with the add/delete/test siblings by being the listing variant, though it never names an alternative explicitly.

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?

There is no guidance on when to use this versus add_watch, delete_watch, or test_watch, and no prerequisites beyond the required key. The lone hint is 'Free,' which signals cost but not selection criteria.

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