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

Annotations already declare readOnlyHint and openWorldHint, so the description earns credit for adding the paid-call model ($0.005 USDC via x402) and the endpoint, plus the percentile return shape. It omits the freshness/window of 'recent' data and failure or rate-limit behavior, keeping it below a 5.

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?

A single front-loaded sentence states the resource, unit, and return distribution, with the pricing footer clearly bracketed as a separate concern. No redundant restatement of the name or annotations.

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 zero-required-parameter read tool with no output schema, the description supplies the return shape, units, and cost model, which is most of what an agent needs. The one gap is the time window behind 'recent' fees, which matters for pricing decisions.

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 both `account` (scoping to a pool/program) and `payment` (x402 signature, free-trial fallback) are already documented in the schema. The description adds no parameter-level detail beyond that, so the baseline 3 applies.

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?

Names a specific resource (recent Solana prioritization fees) with units (micro-lamports per compute unit) and the exact output shape (p25/p50/p75/p90). An agent can distinguish this from sibling fee tools like base_gas purely on chain and output form without opening the schema.

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?

Gives a concrete use case: 'so an agent can price a transaction that lands', which tells the caller this is for fee-setting before submitting a transaction. It stops short of stating exclusions or naming alternatives (e.g., when to use a network-status or transaction-inspection tool instead).

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