mouse_up

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

With no annotations, the description carries the full behavioral burden, but it only restates the operation. It does not disclose state requirements (e.g., whether a button must already be held), what happens if no button is down, or what screenshot_after actually captures. This is thin for a stateful 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?

One short, front-loaded sentence with zero filler and the core operation stated first. The terseness borders on under-specification rather than being genuinely economical, but structurally it is clean.

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 two-parameter tool with no output schema, the description is still missing the pieces an agent needs: the relationship to mouse_down, and the meaning of screenshot_after. Since the schema itself documents nothing, the definition leaves the caller guessing.

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 0% across two parameters, so the description must compensate and does not. The button enum (left/right/middle/back/forward, default left) and the screenshot_after flag are entirely undocumented in prose; screenshot_after in particular is not self-evident about timing or scope.

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 gives a specific verb and resource ("Release a mouse button"), so an agent understands the operation immediately and can distinguish it from unrelated siblings like screenshot or type_text. However, it does nothing to differentiate itself from its nearest sibling, mouse_down, which is the operation agents will most often confuse it with.

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 guidance on when to use this versus alternatives. In particular, the paired sibling mouse_down exists and the natural usage pattern (a mouse_down must precede a mouse_up) is never stated, nor is any context about drag versus click workflows.

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