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

No annotations are provided, so the description fully carries behavioral disclosure. It explains the return shape, the meaning of each source value, and the unreliable nature of 'device' fixes, including the edge case where a valid fix can still return 'none'. This is unusually transparent.

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 is front-loaded with the tool's purpose, then provides a compact but complete breakdown of the response source field. Every sentence adds meaningful information, and the formatting with quoted values and punctuation aids parsing.

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?

With no output schema and no annotations, the description must explain return values and edge behavior, and it does so thoroughly. The single parameter is fully covered by the schema. Nothing necessary for correct invocation or interpretation is missing.

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 the single parameter 'udid' is already documented in the schema. The description adds no parameter-level detail, which is acceptable given the high schema coverage and simple parameter set.

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 opens with a specific verb and resource: 'Read the Android device's current GPS location.' It also names the iOS counterpart, distinguishing it from ios_get_location. The boundary against device_set_location is implicit through the mock-source explanation.

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 clearly indicates this tool is for reading GPS location on Android, and its counterpart relationship with ios_get_location provides routing context. It doesn't explicitly state 'use this instead of X when Y' or list exclusions, but the mock/device/none semantics guide the agent on interpreting results after reading.

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