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

No annotations are provided, and the description carries the full burden well: it discloses that sources are never mixed, that each cell names its source/metric/sample size, that only aggregates are stored (no prompt text), the min_events visibility threshold, and the exact auth/404/403 failure conditions. This is unusually rich behavioral disclosure for an unannotated tool.

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?

Front-loaded with what the tool returns and how it should be used, and nearly every sentence adds information. It is dense but long, and the min_events restatement plus the source-enumeration clause are mildly redundant; still efficient overall.

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 steps in to explain the cell structure (source, quality metric, sample size) and the aggregation guarantee. Combined with auth and error prerequisites, an agent has everything needed to call it correctly.

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%, so the schema already documents both parameters. The description reiterates min_events in narrative form ('appear once a cell has min_events routed calls') but adds little beyond the schema and never explains window_days semantics. Baseline 3 is appropriate.

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+resource ('per-prompt-class quality benchmarks across pricing functions and providers') and enumerates the request classes covered, which cleanly separates it from siblings like get_cost_analytics or get_public_leaderboard. An agent knows exactly what it retrieves without opening the 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?

Explicitly says 'Use it to choose a routing preference or function per kind of request,' giving a clear decision context and gating conditions (routing read scope, 404 until features enabled, 403 for sandbox keys). It does not name specific sibling alternatives to use when this one isn't right, so it falls short of a 5.

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