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

With no annotations, the description discloses critical behavior: metered pricing ($0.002 USDC), 402 payment challenge on unpaid calls, and the free-only-if-rail-disabled condition with a readiness endpoint. This goes well beyond the basic purpose and is essential for an agent to invoke it correctly.

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: the first is a front-loaded purpose statement, the second covers cost and payment behavior. Every word earns its place; no redundancy or fluff.

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?

The description covers the core function, cost, and payment challenge behavior, which is substantial for an 8-parameter tool with no output schema. It doesn't describe the return format or ranking criteria, but that's a minor gap given the complexity.

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%, so all parameters are already documented. The description adds no additional parameter-level semantics beyond what the schema provides, matching the baseline of 3 for high coverage.

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 states a specific action and resource: 'Rank live agents against a task spec using their published manifests.' This distinguishes it from siblings like check_agent_readiness and provides a precise verb-object relationship.

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 context is clear: use this tool to rank agents for task routing. However, it does not explicitly name alternatives or state when not to use it, though it does provide deployment-specific guidance about cost and the readiness check.

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