Start recording a test

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

No annotations exist, so the description carries the full burden; it does disclose the important side effect that the app will be restarted, plus the default app targeting. It omits how the recording is terminated or persisted, what handle/identifier comes back, and what happens to an already-running recording.

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, front-loaded with the action and followed by the default-targeting caveat; every clause earns its place. Sized appropriately for a low-parameter tool.

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 stateful recording tool with no annotations and no output schema, the description establishes the start of a workflow but not its shape—no mention of stopping/saving, of what is captured, or of what the caller receives. Adequate but leaves real workflow 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 coverage is 100%, so all three parameters are already documented. The description adds one genuinely new fact—that the app parameter defaults to whatever is currently on screen—but says nothing about serial or clear_state behavior beyond the schema text.

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?

States a specific compound action: restart the app and begin capturing subsequent actions as a repeatable test. This is clearly distinct from phone_test_save and phone_test_run by wording, and 'record everything you do from here' separates it from a plain phone_start. It stops short of naming those siblings explicitly.

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?

Usage is implied by 'record everything you do from here as a repeatable test' and the note about defaulting to the on-screen app, so an agent can infer this is the entry point of a test-authoring workflow. However, no alternative is named, no prerequisite state is stated, and the implied follow-up (saving with a sibling) is never mentioned.

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