open_url

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

Annotations already declare readOnlyHint=false, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds only the useful detail that the URL opens in the default browser; it says nothing about scheme handling, whether the call blocks, or what happens on failure.

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?

One short sentence with zero waste and the key information front-loaded. It is arguably too terse for a side-effecting tool, but nothing is padded or redundant.

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 one-parameter tool with a complete schema and safety annotations, the basics are covered. Missing are the edge behaviors an agent would want before calling: URL validation/scheme requirements and whether the call confirms the browser actually launched.

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?

Single required parameter with 100% schema description coverage, so the schema already documents it. The description adds no format or validation detail (e.g., required scheme prefix) beyond 'URL to open', which is the baseline 3 case.

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?

Specific verb + resource: 'Open a URL in the default browser' tells an agent exactly what happens and where it happens (default browser, not a specific app). It doesn't distinguish from siblings like launch_app or projector_open_url, but the action itself 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?

No guidance on when to use this versus launch_app, open_file_manager, or projector_open_url. The agent must infer that this is for http(s)-style links and the projector variant is for the projector surface, with no stated exclusions or prerequisites.

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