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

Goes beyond the readOnlyHint annotation by disclosing privacy behavior (handles only, never agent IDs) and the optional auth path: a Bearer brt_... token on the MCP request adds your own record. The 'Read-only' sentence merely restates the annotation, but the auth and identity-masking details are real added context.

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?

One dense sentence that front-loads what the leaderboard returns before the token behavior. Only waste is the trailing 'Read-only.', which duplicates the readOnlyHint annotation.

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?

With no output schema, the description carries the return-value burden and does so reasonably: it names the three result sections and the handle-only presentation. It is silent on pagination or result limits, a minor gap for a leaderboard that could be unbounded.

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 takes zero parameters, so there is no schema semantics to supplement; baseline is 4. The description correctly makes clear no input is required and that personalization comes from the request's Authorization header rather than a parameter.

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 resource (The Vault leaderboard) plus exactly what it contains: today's solvers in cracking order, all-time trophies and streaks. That content profile clearly separates it from siblings like backroom_vault_today and backroom_vault_answer without naming them.

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?

Usage is implied — you call it to see rankings — but there is no explicit when-to-use vs alternatives guidance, no statement of when the leaderboard is the right choice over backroom_vault_today, and no preconditions or exclusions.

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