open_browser

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 adds useful context about supported browsers and URL protocol requirements (implied by the schema), but it does not cover aspects like error handling, platform dependencies, or what happens if the browser is not installed. The description provides some behavioral insight but leaves gaps for a mutation tool.

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 appropriately sized and front-loaded, consisting of a single, efficient sentence that directly states the tool's function and supported browsers without unnecessary details. Every part of the sentence earns its place by providing essential information, making it highly concise and well-structured.

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?

Given the tool's complexity (simple mutation with one parameter), no annotations, and no output schema, the description is moderately complete. It covers the basic action and browser support but lacks details on behavioral traits like error responses or system requirements. For a tool with no annotations, it should do more to fully inform the agent, resulting in an adequate but incomplete description.

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 parameter 'url' fully documented in the schema (including protocol requirements). The description does not add any additional meaning or semantics beyond what the schema provides, such as examples or edge cases. Given the high schema coverage, the baseline score of 3 is appropriate as the description does not compensate or enhance parameter understanding.

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 resource ('in the preferred web browser'), distinguishing it from sibling tools like open_file and open_folder which handle different resources. It provides explicit detail about supported browsers (Firefox, Chrome, system default), making the purpose unambiguous and distinct.

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 by specifying supported browsers, but it does not explicitly state when to use this tool versus alternatives like open_file or open_folder. It provides some context (browser types) but lacks guidance on exclusions or direct comparisons with sibling tools, leaving the agent to infer appropriate usage scenarios.

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