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

Annotations already declare readOnlyHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is covered externally. The description adds valuable context beyond annotations: the value type ('Values are always strings'), the two scopes (Static vs Runtime), their origins (authored vs CloudCode-only), and visibility partitions (Public vs Private). This helps the agent interpret the result structure even without an output schema.

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 (four sentences) and front-loads the core purpose, scope, and exclusions. Every sentence contributes necessary information without redundancy.

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 that there is no output schema, the description does an excellent job of describing the returned data structure (two scopes, each split into Public/Private) and the data type (strings). It also clarifies the boundary with per-player data. It stops short of describing how the data is retrieved or any rate limits, but for a read-only tool with external safety annotations, it is quite 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 for the single parameter is 100%, and the schema itself provides the description. The tool's description does not add parameter-specific details about title_id format or constraints. Baseline 3 is appropriate since the schema already does the heavy lifting.

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 ('Read the TITLE's key-value data store') and immediately distinguishes the content from siblings by naming the alternative data source: 'Per-player data is NOT here — it lives in each player's UserCustomData.' An agent can tell this apart from get_user_custom_data without opening either schema.

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 clarifies when this tool applies by enumerating its contents (event state, global counters, server-side thresholds, feature toggles) and explicitly excludes per-player data, pointing to the UserCustomData store as the alternative. It does not explicitly name the sibling tool get_user_custom_data, but the concept is clear enough to guide selection.

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