Android XR Developer Guide

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

Annotations declare readOnlyHint: true, so the description does not need to reiterate safety. It adds valuable behavioral context, such as the temporal status ('Developer Preview 3, December 2025'), device release info, and a caution about AI-generated code missing spatial value. No contradictions with annotations.

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 verbose, containing multiple paragraphs and extra details (e.g., launch dates, device counts) that go beyond core guidance. While the first sentence front-loads the purpose, the extraneous information reduces conciseness. Some sentences could be removed without losing essential meaning.

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 the tool's complexity (a reference guide with one parameter, no output schema), the description is remarkably complete. It covers the purpose, topics, technical notes (Material 3 auto-spatial, AI code limitations), and compatibility patterns. An AI agent would have a thorough understanding of what to expect and how to use the 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?

The schema covers the 'topic' parameter with 100% coverage, listing five valid topics. The description enriches this by providing detailed context for each topic (e.g., 'overview: concepts, device status'; 'spatial ui: SpatialPanel, UserSubspace, Orbiter'). This adds significant meaning beyond the schema's simple enumeration.

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 clearly states it is an 'Android XR SDK reference' and lists specific topics like 'overview', 'setup', 'spatial ui', 'arcore', and 'compatibility'. The name and title are descriptive and distinguish it from sibling tools (e.g., android_large_screen_guide, android_wearos_guide) by focusing solely on XR.

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 explains when to use this tool (for XR-specific development) and contrasts it with generic Compose development (e.g., 'Standard Compose apps run as 2D panels on XR headsets — no SDK required'). However, it does not explicitly state when not to use it or compare directly with sibling tools, leaving some ambiguity for an AI agent.

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