Open file/folder with a specific app

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

There are no annotations, so the description carries the behavioral burden. It clearly conveys that the tool launches a specific application rather than the OS default handler and that it requires an explicit app choice. It does not discuss side effects or failure behavior, but for a straightforward open action this is sufficient context.

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 three sentences with no wasted content. It front-loads the core purpose and examples, then covers the required-app caveat and the alternative tool. Every sentence earns its place.

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 low-complexity tool with two fully documented required parameters, the description covers purpose, selection criteria, parameter constraints, and the sibling alternative. It does not explain return values, but none are critical for invoking an open-file-with-app action.

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%, so the schema already documents both required parameters. The description reinforces the requirement and adds the 'ask rather than guess' guidance, but it does not meaningfully extend semantic detail beyond what the schema provides.

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 states a specific verb and resource ('Open a file or folder using a SPECIFIC application') with concrete examples. It also distinguishes itself from the OS default handler and sibling tool open_path by emphasizing the explicit app requirement.

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 explicitly says when to call this tool (when a specific app is requested) and when not to (no specific app requested, use open_path instead). It also tells the agent to ask the user rather than guess, which fully resolves the ambiguity between this tool and its sibling.

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