is_device_secure

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

With no annotations, the description carries the burden and does well: it discloses how the value is probed (locksettings), what API semantics it mirrors (KeyguardManager.isDeviceSecure), and why it matters (Keystore checks gate on it). It doesn't mention probing limitations (e.g. shell/root requirements or behavior on older API levels).

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 tightly packed sentences: the assertion first, then the usage context. No filler and the actionable guidance is front-loaded.

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?

A boolean read tool with a fully documented single parameter and no output schema; the description makes the boolean return semantics clear via the API it mirrors. Only the failure modes of the underlying locksettings probe are unaddressed.

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 100% and the single optional 'serial' parameter is fully documented in the schema (adb -s, optional when one device is attached). The description adds nothing parameter-specific, so baseline 3 applies.

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 verb and resource ('Report whether a secure lock screen is set') and grounds it in the concrete mechanism (locksettings / KeyguardManager.isDeviceSecure). This clearly distinguishes it from state-changing siblings like set_device_lock and clear_device_lock, though it doesn't explicitly contrast with has_biometric_enrolled.

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?

Explicitly gives the when: 'verify set_device_lock worked before running a Keystore-gated flow', naming the sibling that produces the state being checked. No explicit when-not or alternative checks are given, which keeps it short of a 5.

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