Query the prior-test registry — has this been tested, and what was the result? (PAID $0.05)

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

The description goes beyond the annotations by disclosing that the call is PAID ($0.05), the transport (POST /v1/edge/prior) and the exact payment rail (x402/base/USDC on eip155:8453) — genuinely useful context given readOnlyHint=false and openWorldHint=true. It stops short of explaining the payment mechanics (e.g. whether a quota preflight or wallet setup is required first) or idempotency/retry behaviour for a non-idempotent paid call.

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?

Very short and front-loaded, with the purpose first and the cost/route second. The only waste is that the first sentence is a verbatim repeat of the tool title, which earns no new information.

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 five-optional-parameter lookup with a 100%-documented schema and an output schema, the description supplies what structured fields cannot: the price, the endpoint, and the payment rail. Nothing an agent needs in order to decide to call it is missing, though the all-optional behaviour of an empty query is unaddressed.

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% and each filter already documents normalisation rules and aliases, so the description adds nothing about parameters. Baseline 3 applies when the schema carries the full burden.

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 and resource ('Query the prior-test registry') and frames the outcome ('has this been tested, and what was the result?'), so an agent knows exactly what it retrieves. It does not differentiate itself from the nearby sibling v1_edge_replication, which sounds like an adjacent prior-test concept, so it stops short of a 5.

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 question framing implies the use case (checking whether a strategy/instrument/timeframe combination has already been tested before spending on a new run), but there is no explicit when-to-use, when-not-to-use, or named alternative such as v1_edge_replication. Usage is left to inference.

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