version

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

Annotations declare readOnlyHint=true and openWorldHint=false, which the description is consistent with. The description adds value by explaining the detection mechanism (environment variable, binary, built-in default), but doesn't describe return format or potential failure modes. No contradiction with annotations.

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, zero waste. Every part earns its place — the verb, resource, and detection mechanism are all conveyed efficiently with no fluff.

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 simple 0-parameter informational tool with an output schema present, the description is appropriately complete. It explains how the version is determined, which is the main behavioral nuance. Minor gap: doesn't mention the built-in default value or what the output format resembles, but with an output schema present, return-format explanation is not required.

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 0 parameters, so the description need not document any. With schema coverage at 100% (empty schema), the baseline for 0 params is 4, and the description correctly avoids inventing parameters.

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 clearly states the tool reports which scrcpy version the MCP server is using, with specific verb ('report') and resource ('scrcpy version'). It also explains the detection order, distinguishing it from any sibling 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?

There is no explicit guidance on when to use this tool versus alternatives, nor any exclusions. It's a simple informational tool with no sibling competitors, so context is somewhat implied, but no usage guidance is provided at all.

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