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

Annotations declare this is a non-read-only, non-idempotent, non-destructive operation, so the description carries less burden. The description adds platform-specific mechanics (APK/IPA installation methods), but it doesn't disclose prerequisites like device connectivity, potential side effects (e.g., overwriting existing app data), behavior on insufficient storage, or whether the install is silent or requires user interaction. This is a gap for a mutation tool with side effects.

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 three short sentences, front-loaded with the core action and platform nuances, and ends with a crucial prerequisite. Every sentence earns its place with no wasted words.

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 two-parameter mutation tool with no output schema and low annotation coverage, the description is adequate but incomplete. It covers the basic action and prerequisite but omits behavioral details like error conditions, side effects, and return information, which an agent would need to invoke it correctly in an automation flow.

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 both parameters (udid, appId) are already documented in the schema. The description adds a hint that appId comes from app_list, but that's also in the schema's parameter description. No additional syntax or format details are provided beyond the schema, so baseline 3 is appropriate.

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 states a specific verb+resource ('Install an uploaded app') and clarifies it works on a device, with platform-specific detail (APK via Android transport, IPA for iOS). It distinguishes itself from app_upload and app_list, though the cross-platform nature overlaps with ios_install_app, a sibling that is not mentioned.

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?

It explicitly tells the agent to 'Use app_list to get the file ID first', which provides a clear prerequisite and points to a sibling tool. However, it doesn't address when to use this multi-platform tool versus the platform-specific ios_install_app.

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