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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds valuable behavioral context beyond annotations: it states 'without external browsing or model inference', which clarifies execution constraints, and discloses 'Price: $0.01 USDC via x402' as a cost/fee detail. The 'up to 25' limit also adds operational context. No contradiction 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?

The description is two sentences, front-loaded with the main action ('Rank up to 25 caller-supplied providers'), and includes essential constraints and pricing in minimal words. Every sentence earns its place; no redundant content.

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?

This is a moderately complex tool with 4 parameters, nested objects, and no output schema. The description doesn't explain the return value/ranking output format, how constraints are structured, or error behavior. Since there is no output schema, the description must carry more weight for completeness, but it omits these critical details, leaving the agent under-informed.

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 must compensate. It maps 'providers' and 'constraints' to the ranking dimensions (price, reliability, latency, evidence, capability, escrow), and 'capability' appears as a param. However, 'requestId' and the structure of 'constraints' are not explained. The description adds partial meaning beyond the schema but does not fully cover all parameters.

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 the tool's purpose: 'Rank up to 25 caller-supplied providers against explicit price, reliability, latency, evidence, capability, and escrow constraints.' The verb 'rank' and the specific constraints differentiate it from sibling tools like proofroute-verify, which likely verifies rather than ranks/selects.

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: the description indicates when to use the tool (when ranking caller-supplied providers against constraints) and states limitations ('without external browsing or model inference'), but it does not explicitly mention when not to use it or direct users to alternative tools. No exclusions or alternative references are provided.

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