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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description doesn't need to establish the safety profile. The description adds the useful detail that BOTH platform and adapter versions are returned, which goes slightly beyond the tool name alone. It doesn't over-explain a simple operation.

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 conveys complete meaning with zero filler. Perfectly sized for the tool's simplicity.

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 the tool's minimal complexity (0 parameters, no output schema, no nested objects), the description is fully complete. It tells the agent exactly what to expect without unnecessary elaboration.

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?

With zero parameters, the 100% schema coverage is vacuous, but the rubric sets a baseline of 4 for this case. The description provides all necessary context since there's no parameter syntax or format to document.

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 resource ('current MCP platform and adapter versions'). It clearly distinguishes this from sibling tools like `connect` or `expo_build_run`, making it evident this is a version-inspection utility.

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?

While it doesn't explicitly name alternatives, the context is clear: this is the tool to call when version information is needed. The simplicity of the tool combined with the contrast against feature-heavy siblings makes the usage context self-evident, though it lacks explicit exclusionary language.

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