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

With no annotations, the description carries the full burden and does well: it discloses the data provenance, full-slot coverage, and the x402 paywall/auth requirement. It stops short of mentioning response size, ordering, or failure behavior, but the main safety and access traits are transparent.

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 two well-structured sentences: the first front-loads the output, the second adds provenance and access context. There is no filler or redundant restatement of the title.

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 the absence of an output schema, the description does a good job describing the returned statistics and histogram. It is slightly incomplete in not specifying the response shape/ordering or whether the histogram is per-builder or aggregate, but for a read-only analytics tool with two simple parameters, it is largely sufficient.

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 input schema already describes both parameters (limit and window_ms) with defaults and clamping, so the description adds little parameter-specific value beyond mentioning a 'configurable window.' With 100% schema coverage, 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?

The description clearly identifies the resource: per-builder bid distribution with specific percentiles and a 24-element hourly slot histogram over a configurable window. It also differentiates from siblings by noting the shadow-recorder source and full slot coverage, though it does not explicitly name an alternative tool.

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 gives clear context: this is a premium/paid tool requiring authentication, and the shadow-recorder source implies use cases needing complete slot coverage rather than just landed blocks. However, it does not explicitly state when to prefer this over sibling tools like builder_leaderboard or when not to use it.

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