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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description goes further by disclosing the data source (public GraphQL, since JSON-RPC is deprecated) and the commercial terms: $0.002 USDC per successful call via x402 on Base, Solana or Arc, with failed calls not charged. That payment/failure policy is behavior an agent cannot get from the schema. It omits freshness/caching cadence for 'current' epoch data, keeping it at 4.

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 total, with the returned fields front-loaded and the exclusion and pricing following in logical order. There is mild redundancy between the phrase 'current epoch from the public GraphQL API' and the later RPC remark, but no filler sentences.

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?

With an output schema present and zero parameters, the description need not document return shapes, yet it still lists the key fields. Annotations cover read-only access and the pricing policy is disclosed. The remaining gap is the misleading tool name ('move_objects' returning epoch data) which the description corrects but does not fully reconcile, plus no note on how current the epoch snapshot is.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter semantics for the description to add. The description correctly implies a parameterless single-shot call, and nothing in it misdescribes inputs.

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 names a specific resource and enumerates exactly what is returned: epoch number, reference gas price in MIST per gas unit, epoch start/end times, and total checkpoints, sourced from Sui mainnet's public GraphQL API. It also preempts a likely confusion from the tool name 'move_objects' by stating shared objects and package ids are NOT included. It stops short of naming a specific sibling alternative, so it lands at 4 rather than 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?

Usage is only implied: an agent can infer this is the tool for Sui epoch/gas-price data and that it must not be used for object lists. There is no explicit 'use this when' clause and no routing to alternatives among the ~90 crypto siblings (e.g. crypto_polygon_pos_checkpoints or crypto_ethereum_gas_telemetry for the analogous metric on another chain).

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