open-url

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

Discloses return value, failure modes (no registered app or rejected navigation), and platform-dependent behavior. Lacks explicit mention of side effects or state changes, but navigation actions are inherently stateful.

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?

Five sentences with no redundancy, front-loaded with the primary action. Each sentence contributes unique value: action, usage, scheme details, return value, and error conditions.

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?

Covers return format and failure scenarios, which is sufficient for a navigation tool without an output schema. Could elaboratate on the 'opened' boolean semantics or wait behavior, but overall adequate.

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 description adds practical examples for the 'url' parameter beyond the schema, illustrating cross-platform and platform-specific schemes. The 'udid' parameter is well-described in the schema, and the description reiterates its source.

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 it opens a URL or URL scheme, lists specific examples, and explicitly differentiates from sibling tools like 'launch-app' by focusing on deep-linking and web navigation.

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?

Provides clear usage context ('Use to navigate to a web page or deep-link into an app') and mentions platform-specific schemes. However, it does not explicitly state when not to use or provide direct comparisons with sibling tools like 'launch-app'.

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