Open File

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals that the file is handed off to whatever app handles its type, which is useful, but it does not mention side effects, permissions, whether the app opens visibly, or what happens if the file type has no handler. This is a significant gap for a tool that triggers external behavior.

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 a single, front-loaded sentence with no filler. It is appropriately concise for a simple tool, though the brevity comes at the cost of important behavioral and parameter context.

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?

With no annotations, 0% parameter schema coverage, and an output schema that is not described in the text, the description leaves too much unexplained. It does not cover device targeting, failure modes, or the implications of launching an external app. A basic agent might invoke it correctly by name, but it would lack the context needed to use it safely and effectively.

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%, so the description must compensate. It only indirectly clarifies that path refers to the file to open, but it says nothing about the optional device parameter or how device selection affects the operation. The schema's raw types and default do little to explain the semantics, leaving the agent under-informed.

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 clear verb and resource: it opens a file using the system's default handler for that file type. It is distinguishable from sibling tools like launch_app and open_deeplink because it focuses on file paths rather than apps or links. It does not explicitly call out sibling tools, but the action is unambiguous.

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 the tool is for opening an existing file, but gives no guidance about when to prefer it over find_files, launch_app, or open_deeplink. There are no explicit conditions, exclusions, or alternative recommendations, so an agent must infer the appropriate context.

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