MCP Appium Server

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

With no annotations provided, the description carries full burden but only states the basic action. It doesn't disclose behavioral traits like: whether this requires device permissions, if it's reversible only via 'unlock-device', potential side effects (e.g., interrupting current activities), or what happens when durationSec expires. For a mutation tool with zero annotation coverage, this is inadequate.

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 perfectly concise at 4 words, front-loaded with the core action. Every word earns its place with zero waste or redundancy.

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 device mutation tool with no annotations and no output schema, the description is incomplete. It should explain what 'locking' means in this context (just screen? full device?), what happens after locking, how to verify success, and relationship to sibling tools like 'is-device-locked' and 'unlock-device'.

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% (durationSec clearly documented), so the baseline is 3. The description doesn't add any parameter semantics beyond what's in the schema - it doesn't explain default behavior if durationSec is omitted, valid ranges, or units clarification beyond 'seconds'.

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 'Lock the device screen' clearly states the action (lock) and target (device screen) with a specific verb+resource. However, it doesn't distinguish from sibling 'unlock-device' or clarify if this is physical device locking versus screen timeout locking, which would be needed for a perfect score.

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 like 'unlock-device' or other device control tools. There's no mention of prerequisites (e.g., device must be unlocked first) or typical use cases (security, testing scenarios).

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