mouseDown

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

Annotations already disclose the important behavioral traits (destructiveHint=true, idempotentHint=false, openWorldHint=true), so the bar is lower. The description adds genuine value beyond them by stating the trust/ownership and interactive-desktop prerequisites, but it omits the defining behavior of a press-and-hold tool: the button remains down until mouseUp, which affects subsequent calls.

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 short sentences with no filler, and the identifying information is front-loaded. A slightly longer description could have earned the space by explaining the hold semantics, but nothing present is wasted.

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 one-parameter, no-output-schema action tool with rich annotations, this is close to adequate. The missing piece is the stateful press-and-hold contract and its pairing with mouseUp, which an agent must know to sequence calls correctly.

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% with a single enum-constrained 'button' parameter, so the schema fully documents the input. The description adds nothing about the button parameter, so the baseline 3 applies.

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 names the tool ('mouseDown') and adds platform context (Windows AutoIt), so the agent knows it is a low-level mouse-press action rather than a generic click. However, it largely restates the tool name and never articulates what the action actually does (press and hold a mouse button), which is the distinction that separates it from mouseClick.

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 mouseDown instead of mouseClick, mouseUp, or mouseMove, all of which appear in the sibling list. The closest the description comes to usage context is the environment prerequisite, which is a precondition rather than a selection rule.

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