open_url

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

With no annotations provided, the description carries the full behavioral burden. It discloses one meaningful trait — Android selects the handling app via intent, so the tool has no control over which app opens — which is genuinely useful context. However, it doesn't disclose side effects like launching an external app that takes over the screen, failure modes when no app handles the URL, or whether the call blocks or returns immediately.

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 one front-loaded sentence plus a single clarifying clause about intent-based routing, with no wasted words. Its compact size is appropriate for a simple tool, aside from the minor stylistic inconsistency of a Hungarian sentence attached to an English tool name.

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 2-parameter, no-annotation tool with 0% schema coverage, the description covers the core action and the app-routing behavior, and the presence of an output schema relieves it of explaining return values. But it leaves the serial parameter undocumented, omits failure handling, and doesn't warn that opening a URL will switch the device to an external app. It is minimally viable with clear gaps.

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?

Schema description coverage is 0%, so the description must define the parameters itself. It implicitly conveys what 'url' means (the URL to open) through the tool's overall statement, but it never explicitly names the parameter. The 'serial' parameter (likely a device identifier given sibling device_list/device_info tools) is entirely unexplained, leaving a required-in-context semantic gap.

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 states a clear action — opening a URL in the default application (browser, map, YouTube) — which is a specific verb+resource combination. It goes beyond the tool name by clarifying that Android resolves the handler app via intent. It is clearly distinct from all listed siblings, none of which open URLs, though the Hungarian phrasing with an English tool name is a minor presentation inconsistency.

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 is given about when to use this tool versus alternatives, and no sibling tools are referenced. The only context is that Android decides which app handles the intent, which describes behavior rather than usage conditions, exclusions, or selection criteria. This is effectively no usage guidance.

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