MCP Scrcpy Vision

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool returns values but doesn't describe what 'getprop' entails (e.g., system properties), potential errors (e.g., if device is unavailable), output format, or side effects. For a tool with no annotation coverage, this leaves significant gaps in understanding its behavior.

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 a single, efficient sentence: 'Returns a subset of getprop values for a device.' It's front-loaded with the core action and resource, with no wasted words. Every part of the sentence contributes to understanding the tool's purpose.

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 no annotations, no output schema, and a simple but undocumented parameter, the description is incomplete. It doesn't explain what 'getprop' is, what subset of values is returned, or the output format. For a tool that interacts with Android devices, more context is needed to use it effectively without trial and error.

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 input schema has one parameter ('serial') with 0% description coverage, and the tool description doesn't mention parameters at all. However, since there's only one parameter and it's straightforward (device serial identifier), the baseline is 3. The description doesn't add meaning beyond the schema, but the simplicity of the parameter keeps the score from dropping lower.

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's purpose: 'Returns a subset of getprop values for a device.' It specifies the action (returns), resource (getprop values), and scope (subset, for a device). However, it doesn't explicitly differentiate from sibling tools like 'android.devices.list' (which likely lists devices rather than returning their properties).

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., device connectivity), when-not-to-use scenarios, or how it relates to siblings such as 'android.devices.list' or 'android.shell.exec' (which might run arbitrary commands). Usage is implied only by the tool name and description.

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