ACTION_GET_SIM_INFO

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

No annotations are supplied, so the description carries the full burden. It does well on prerequisites (READ_PHONE_STATE) and on output shape and formatting (comma-separated lists, possible empty sim_numbers, variable-snapshot JSON return), but it says nothing about failure behavior, whether a permission denial throws or returns sim_error, or interaction with the require/on_error parameters.

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?

Dense and front-loaded: capability, permission, outputs, then caveats. The only blemishes are a doubled full stop and a slightly cluttered inline enumeration of output fields, but no sentence is wasted.

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, the description correctly compensates by listing the returned fields and their formats. Since all four input parameters are fully described in the schema, the remaining omission (error semantics when permission is missing) is minor for a read-only probe tool.

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 the baseline is 3; the description earns an extra point by documenting cross-cutting behavior not in the schema, namely that string parameters support ${var} interpolation and that results are persisted as a variable snapshot.

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: reading SIM count, carrier and phone number, and it enumerates the exact outputs (sim_count, sim_carriers, sim_numbers). It does not explicitly distinguish itself from nearby siblings such as ACTION_GET_DEVICE_INFO, ACTION_GET_CALL_STATE or ACTION_NETWORK_STATUS, which an agent could plausibly confuse with SIM data.

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 context is implied by the READ_PHONE_STATE permission note and the caveat that many SIMs do not store a local number, so agents know to expect empty results. There is no explicit when-to-use or when-not-to-use guidance relative to the other device/network state tools.

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