Lock the screen

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

No annotations exist, so description fully owns behavioral disclosure. It clearly states the side effect (locks screen), reassures that applications keep running and nothing is closed, and declares it safe anytime. This is excellent transparency for a no-parameter action.

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 concise sentences, front-loaded with the core action, then reassurance. No wasted words, no 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 zero-parameter, no-output-schema tool, the description covers all essential aspects: what it does, how, and safety implications. Complete and self-sufficient.

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?

Tool has zero parameters, so schema coverage is 100% and no parameter documentation is needed. Description adds context about the action itself, which is sufficient.

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?

Description explicitly states the tool locks the Mac immediately, compares to pressing the lock shortcut, and clarifies scope (no apps closed). This is clear and distinct from all sibling tools, none of which perform locking.

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?

Provides clear usage context: safe to invoke at any time because applications continue running. Does not explicitly mention when not to use or name alternatives, but given uniqueness and zero params, it is adequate.

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