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

With no annotations, the description carries the full behavioral burden and does so well: it discloses update frequency (15s), Solana compute-unit pricing semantics, supported EVM chains, x402 payment flow, retry behavior, and that unpaid/failed calls are not charged.

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 dense but front-loaded: purpose first, then supported chains, update frequency, chain-type caveat, sibling routing, and payment mechanics. It is somewhat long, but most sentences carry operational value for an agent.

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?

Given no output schema, the description explains the return content at a useful level: gas tiers (slow/standard/fast) plus USD costs for a transfer, USDC transfer, and swap. It also covers pricing semantics, freshness, supported chains, sibling alternatives, and payment requirements.

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 schema already covers the single required 'chain' enum at 100%, so baseline is 3. The description adds useful meaning beyond the enum by clarifying the six supported chains and calling out that Solana uses compute-unit pricing rather than gwei-style gas.

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 states a specific verb/resource ('Current gas/fee tiers and USD costs') and explicitly scopes it to one chain. It distinguishes itself from siblings by naming compare_gas_costs and estimate_custom_tx_cost and explaining the difference.

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?

It gives explicit when-to-use guidance: use for one chain's prices, use compare_gas_costs to rank all six, and use estimate_custom_tx_cost for custom gas limits or compute budgets outside the three canned transaction types.

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