Open a URL / deep link

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

Annotations already cover the mutation/safety profile (readOnlyHint=false, destructiveHint=false), so the description's main contribution is the ACTION_VIEW intent detail, which tells the agent the URL is routed through Android's intent resolution to whatever app handles the scheme. It does not disclose what happens when no handler exists, whether an error or silent success is returned, or what the tool call produces.

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?

A single front-loaded sentence with no filler or redundancy. It is efficient, though its brevity is close to under-specification rather than model conciseness.

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 two-parameter tool with no output schema and only default annotations, the description leaves meaningful gaps: failure behavior when no activity handles the intent, the device-selection default, and any indication of what a successful call yields. The core action is clear, but an agent cannot anticipate edge cases from this text.

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 50%: 'serial' is documented in the schema, but 'url' carries no description, format, or example. The ACTION_VIEW mention hints that a scheme-style deep link is acceptable, but the description adds nothing about URL formatting, allowed schemes, or encoding, so it barely compensates for the undocumented required parameter.

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 specific verb and resource ('Opens a deep link or URL') and adds the underlying mechanism ('ACTION_VIEW intent'), which is more precise than the title alone. It does not, however, distinguish itself from ios_open_url or clarify how it differs from android_launch_app, so sibling differentiation rests entirely on the tool name.

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?

There is no guidance on when to pick this over android_launch_app (deep link vs. launching a package) or when this is inappropriate. It also says nothing about device preconditions, e.g. that a target device must be online or that serial defaults to the sole connected device.

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