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. It does disclose the key side effect — it hands the file to an external GUI application — but says nothing about whether the call blocks or returns immediately, what happens if no default app is registered, or whether it mutates anything.

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?

A single front-loaded sentence with the mechanism stated before the examples; nothing wasted and nothing buried.

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?

An output schema exists, so return values need not be explained, and the description covers purpose and dispatch behavior adequately for a one-parameter tool. The remaining gap is the lack of differentiation from freecad_run_file, which matters given the sibling set.

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% for the single 'path' parameter, so the description must compensate. The extension-based examples hint that the path determines which application is launched, but it never states path format (absolute vs relative), or error behavior for unknown extensions.

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?

States a specific verb ('Abre') and resource ('o arquivo') plus the mechanism (default system application), with concrete dispatch examples (3MF → Bambu Studio, FCStd → FreeCAD) that make the behavior unambiguous. It does not explicitly contrast with the sibling freecad_run_file, which also operates on a file, so the agent must infer the distinction from the examples.

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?

Usage is only implied: an agent can infer 'use this to view/open a file' but there is no statement of when to prefer freecad_run_file or freecad_run instead, nor any preconditions (file must exist, extension must be associated).

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