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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read profile is covered structurally. The description adds only 'public' as behavioral context and says nothing beyond that about pagination behavior or data freshness, so a baseline 3 fits.

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?

Two sentences: purpose front-loaded, then the prerequisite/alternative guidance. No filler, every clause earns its place.

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 2-parameter read-only list tool with an output schema (return values need no explanation) and annotations covering the safety profile, the description supplies purpose plus how to obtain the required ID. Nothing an agent needs to call it correctly 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?

Schema description coverage is 100% (cursor and universe_id both documented), so the schema carries parameter meaning. The description privately clarifies that the ID refers to an experience/universe, a small value-add, but doesn't define syntax or ID sourcing beyond naming helper tools.

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?

States a specific verb and resource with scope: 'List public achievement metadata for one Roblox experience ID.' An agent immediately knows this returns badge/achievement data for a single universe, distinct from roblox_game (game info), roblox_search (lookup), and roblox_rankings (comparison).

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?

Explicitly names the prerequisite path: use roblox_game or roblox_search to obtain an experience, or roblox_rankings to compare games. This tells the agent how to source the required universe_id and which siblings serve adjacent needs, though it never states when NOT to use this tool.

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