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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful behavioral context beyond those flags: it is a paid resource with a specific per-call price, and it performs ranking using caller-supplied signals, weights, and constraints. It does not describe output or failure semantics, but it does not conflict with annotations.

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 sentences deliver the function, intended usage, exclusions, and cost with no filler. The core ranking behavior is front-loaded, and every sentence earns its place.

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 tool with nested parameters, no output schema, and no parameter descriptions, the description misses some operational detail: it does not explain what the returned ranking looks like, how constraints filter or rank, or the meaning of 'price unknown.' Still, it covers purpose, exclusions, inputs, and cost, so it is adequate but not complete.

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 0%, so the description carries the burden. It names the relevant signal dimensions and mentions 'constraints and weights', which maps to the weights and constraints objects. However, it does not clarify optionality/defaults, exact mapping to fields like price_usd and latency_ms, or the boolean permission/payment candidates, so the compensation is partial.

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 opens with a specific verb and object: 'Ranks caller-supplied candidates', and specifies the exact signals (price, reliability, latency, trust, quality) and the role of constraints and weights. The 'selection routing / price unknown' intent plus the explicit prohibition on legal/identity/sanctions/fraud/contractual/regulatory adjudication make it distinguishable from the broad set of policy, verification, and control-plane sibling tools.

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 clearly states when to use ('Intended for selection routing / price unknown') and gives an explicit negative list ('Do not use for legal, identity, sanctions, fraud, contractual, or regulatory adjudication'). It does not point to a named alternative tool, so it stops short of full 5 for alternative routing.

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