open_in_app

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

Annotations already indicate non-destructive and open-world behavior. The description adds the fallback to browser preview, which is behavioral context beyond the annotations. No contradictions.

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 sentences convey all necessary information without redundancy. The description is front-loaded with the core action and immediately provides key constraints (macOS only, fallback).

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 tool with one required parameter and no output schema, the description covers purpose, platform, and fallback behavior. It addresses the essential context an agent needs to invoke the tool 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?

The input schema covers the single parameter 'dgmo' with description 'DGMO diagram markup', which is sufficient. The tool description does not add further parameter details, but 100% schema coverage means baseline 3 is appropriate.

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 clearly states the tool's action: opening a DGMO diagram in the Diagrammo desktop app. It also specifies the platform (macOS only) and distinguishes from sibling tools like preview_diagram by targeting the desktop app specifically.

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 indicates when to use the tool (to open in desktop app) and includes fallback behavior if the app is not installed. However, it does not explicitly mention alternatives or when not to use this tool compared to other preview tools.

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