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

With no annotations provided, the description carries the full burden of behavioral disclosure and does so excellently. It discloses side effects (auto-installs helper service on first call), version requirement (API 26+), app-wide scope, and the crucial limitation that mock-detection-aware apps will refuse the fix. This is exemplary transparency for a tool with zero annotation coverage.

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 packs significant useful detail into three sentences without wasted words. It's slightly dense but every clause earns its place — scope, mechanism, version constraint, and limitations all covered with minimal fluff. Not maximally concise because the sentences are somewhat long, but highly efficient overall.

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?

Given zero annotations, no output schema, and a tool that mutates device state, the description provides comprehensive context: what it does, how it works (bundled helper service), version requirements, scope, and inherent limitations. The isFromMockProvider caveat is exactly the kind of operational nuance an agent needs before invoking.

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%, so all 4 params (udid, latitude, longitude, accuracy) are already documented in the schema. The description adds no additional parameter-level meaning beyond what the schema provides, but the baseline of 3 is appropriate when the schema fully covers params.

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 specifies a clear verb+resource+scenario: 'Mock GPS coordinates on an Android device for testing location-aware apps.' It precisely distinguishes from siblings like ios_set_location and device_clear_location by naming the platform (Android) and the mock mechanism. This is excellent purpose clarity.

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?

The description provides clear usage context (testing location-aware apps, API 26+ constraint, scope across apps). It doesn't explicitly name alternative tools or when NOT to use it, though the ios_ siblings make the Android scope implicit. The 'apps that check isFromMockProvider' warning effectively signals limitations on when this mock approach works.

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