back

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does clarify the two distinct modes and their intent, but it omits potential side effects (e.g., system back may exit the app) and does not describe outcome or error behavior.

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 only two sentences, front-loaded with the core purpose, and contains no redundant or filler content.

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 output schema and high parameter coverage, the description provides the key decision context (mode selection). It does not disambiguate from sibling tools like close or home, but the mode explanation makes the tool adequately self-contained.

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 96%, so the baseline is 3. The description adds meaningful semantics to the mode parameter by defining what in-app and system mean, which is not present in the schema itself.

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 uses a specific verb ('Navigate back') and clearly defines the two scopes: in-app navigation stack and system navigation. This distinguishes it from sibling tools like home, close, or app-switcher.

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 states when to use in-app vs system mode ('Use in-app for the app navigation stack and system when the platform back behavior is required'). It does not name alternative sibling tools, but it gives clear situational guidance.

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