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

Annotations already declare this is a non-read-only, non-idempotent, destructive write; the description goes beyond them by disclosing that `id` is immutable after creation and that no delete path exists. It does not describe what happens on a duplicate tag or permission/error behavior, so it is useful but not complete.

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?

Three short sentences, front-loaded with the purpose, then the two constraints that actually affect the call. No redundancy or filler.

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 6-parameter create tool with full schema coverage and a rich enum-laden schema, the description covers purpose, the immutability constraint, the pre-check requirement, and the absence of a delete counterpart. No output schema exists, so return values need not be described.

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% and the parameter descriptions are already rich (enums, defaults, semantics), so the baseline is 3. The description still adds genuinely new information: `id` is not changeable later, which the schema does not state.

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 first sentence gives a clear verb+resource ('Add a leaderboard to a game'), immediately distinguishing this from read/update siblings. It does not explicitly contrast with update_leaderboard, the closest sibling, so it falls short of a 5.

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 routes the agent to a sibling with a condition: 'Check list_leaderboards for tags already taken,' and states a limitation the agent must plan around ('Deleting a leaderboard is not available'). It never states when to choose create vs update_leaderboard, so it stops short of explicit when/when-not guidance.

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