read_phone

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

With no annotations, the description carries the full burden and does disclose the key destructive trait: unapplied drafts are discarded. It does not cover failure modes (no device connected) or whether the read is live versus cached, so it stops short of full behavioral disclosure.

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?

Two short sentences, zero waste, with the destructive warning placed immediately after the action so it is read before invocation.

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?

An output schema exists, so return values need not be explained, and there are no parameters to document. The remaining gap is device-connection preconditions and error behavior for a tool whose name implies hardware dependency.

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 tool takes zero parameters, so the baseline is 4; there is nothing for the description to disambiguate. The schema is empty and unambiguous on its own.

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 and resource ('Read the Home Screen from the connected iPhone') plus the side effect of seeding a new working draft. It is distinguishable from siblings like screen_time or show_layout, but it does not explicitly differentiate itself from reset_draft, which also clears draft state.

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?

'Start a fresh draft from it' implies this is the entry point of the edit workflow, which suggests when to reach for it. However, there is no explicit guidance on when to prefer reset_draft, undo, or restore, and no stated preconditions such as requiring a connected device.

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