mouse_up

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

The description adds behavioral context beyond annotations by mentioning the optional move-before-release and the VM lock persistence. It does not contradict the idempotentHint or destructiveHint annotations, and the disclosure is adequate for a simple input tool.

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 with no fluff. The first sentence names the core action, and the second provides essential lock-related instructions. Every word contributes value.

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 mouse input tool, the description plus schema and annotations cover the action, optional parameters, and the lock lifecycle. It does not explicitly mention the sequence ('use after mouse_down') or compare with mouse_release_all, but those gaps are minor given the tool's simplicity.

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 already describes x/y as coordinates. The description adds that these are optional movement targets before release, which clarifies why they are optional. The button parameter is self-explanatory via its enum and default, and the description's 'held mouse button' ties it to the action.

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 phrase 'Release a held mouse button' is a specific verb+object description that clearly differentiates this tool from siblings like mouse_down, mouse_click, and mouse_release_all. It also adds the optional movement behavior, which further clarifies its scope.

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 implies usage when a mouse button is currently held and optionally after moving to coordinates. The VM lock note gives important sequencing context ('call vm_unlock when finished'), though it does not explicitly compare against alternatives like mouse_release_all.

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