macos_open_url

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action but doesn't mention system permissions required (e.g., accessibility settings), whether it opens in foreground/background, potential user confirmation dialogs, or error handling for invalid URLs. This leaves significant behavioral gaps for a system-level operation.

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, efficient sentence that states the core functionality without any unnecessary words. It's front-loaded with the main action and provides just enough context about the execution environment (default web browser).

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 parameter and 100% schema coverage, the description is minimally adequate. However, without annotations or output schema, it should ideally mention what constitutes success/failure or any system feedback. The description covers the basic action but lacks completeness regarding behavioral expectations and system integration details.

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 schema description coverage is 100% with the single 'url' parameter well-documented in the schema. The description doesn't add any parameter-specific information beyond what the schema provides, such as URL format requirements or validation rules. This meets the baseline for high schema coverage.

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 specific action ('Open a URL') and the target resource ('in the default web browser'), making the purpose immediately understandable. It distinguishes itself from sibling tools like 'macos_open_with_default' by specifying the browser context rather than general file opening.

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 usage for opening URLs in web browsers, but provides no explicit guidance on when to use this tool versus alternatives like 'macos_open_with_default' for files or other macOS-specific tools. It lacks any mention of prerequisites, exclusions, or specific scenarios where this tool is preferred.

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