Shared preference catalog

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

Annotations already declare readOnlyHint=true, and the description reinforces this with 'Read-only' while adding context about engine ownership, the settings app rendering, and the boundary with oma.pref(). This adds useful behavioral context beyond the 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 compact and front-loaded, but the phrase 'Read-only.' is redundant given readOnlyHint=true. Still, both sentences earn their place by explaining ownership, rendering, and the oma.pref() distinction.

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 zero-parameter read-only catalog tool with an output schema, the description is complete: it names the resource, the contents, the consumers, and the boundary against runtime value retrieval. Nothing essential is missing.

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 tool has zero parameters and schema description coverage is 100%, so there is no parameter information to add. The description still clarifies what the catalog entries contain (key, type, label, default, options), which helps an agent understand the output.

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 ('describes') and resource ('engine-owned catalog of SHARED preferences'), and clearly distinguishes the tool from effective-value retrieval by noting that apps read values via oma.pref() while this tool only describes what exists.

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 implies the intended use: inspect the catalog of shared preference definitions rather than read effective values. It explains the relationship to oma.pref(), though it does not explicitly name alternatives or state when not to use it.

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