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

With no annotations, the description carries the full burden and does disclose the two most consequential traits: the tool is paid (0.001 USDC per call via x402) and the first invocation does not return data but payment instructions. It does not state data freshness/update cadence or whether results are cached, which an agent quoting gas prices would want.

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 short sentences, each carrying distinct information: EVM metrics, Solana metrics, price. No filler and the most important content (what you get) is front-loaded.

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 two-parameter read tool with no output schema, the description plus schema cover what is returned, in what units, and how payment works. Only freshness/cadence and failure behavior are left unstated, which is a minor gap rather than a blocking one.

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%, including a full explanation of paymentProof and its 402 handshake, so the schema does the heavy lifting. The description adds per-chain output-unit context that helps the agent pick a chain value, but nothing about the chain enum or parameter behavior beyond what the schema already says.

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 exactly which metrics are returned and splits them by chain family (EVM base/priority fee/gas price in gwei vs Solana prioritization fee percentiles in micro-lamports per CU). That is specific enough to distinguish it from siblings like crypto_price or solana_network, though it never says so explicitly.

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 by the resource fetched; there is no statement of when to prefer this over crypto_price or solana_network, and no prerequisites beyond the payment note. The two-step 'first call returns 402, then retry with proof' procedure is the only concrete usage guidance offered.

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