getCapabilityGuide

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

No annotations, so description carries full burden. It discloses return content (minimal Kotlin + Swift snippet, gotchas, related getCodeExample patterns) and limitations ('minimal', 'typically cover it'). It doesn't explicitly state read-only behavior, but the guide nature implies non-mutation, and no hidden side effects are indicated.

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?

Front-loaded with a clear purpose, followed by relationship to siblings, coverage list, and usage guidance. The 'Covers' feature list partially duplicates the schema enum, but adds semantic grouping that aids understanding. The USE/DON'T USE sections are succinct and effective.

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?

No output schema, but description fully explains return content and boundaries. It covers what the tool does, when to use it, when not to, and how it relates to siblings. For a lookup guide with one parameter, the description is comprehensive and complete.

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% (enum + description referencing getPlatformInfo.features[].name). Description adds value by semantically grouping feature types (lower-level primitives vs assistant runtime) and advising to start with 'assistant_runtime' for voice-assistant apps, which helps parameter selection beyond the schema.

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 explicitly defines the tool as a 'Per-feature SDK usage guide' with Kotlin/Swift snippets, gotchas, and related code patterns. It distinguishes from siblings by stating it adds 'the actual idiom' for feature usage, while getPlatformInfo only lists names/categories and getCodeExample provides full patterns.

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?

Provides clear USE conditions ('when you know which feature you need but don't know the canonical call shape, or when you're hitting a confusing failure') and explicitly names alternatives for DON'T USE cases (getCodeExample for compositional patterns, getPlatformInfo for capability discovery).

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