chain_call

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

With no annotations, the description carries the full burden and does so well: it declares read-only safety, discloses that the call is paid, quantifies the cost (0.02 USDC on Base via x402), and reveals return behavior (decoded revert reason). It omits rate limits and failure/refund semantics on the paid path, keeping it short of 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?

It is a single information-dense sentence with the core action front-loaded and no filler. The stacked parentheticals are slightly compressed but nothing is wasted.

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 7-parameter tool with no annotations or output schema, the description covers the essentials an agent needs: read-only nature, payment model and cost, and revert decoding behavior, with the schema supplying parameter detail. Missing rate limits and partial-call/failure handling keep it from complete.

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 86%, so the schema already documents almost every parameter (to, from, data, block, confirmNewPurchase, etc.). The description adds no parameter-level detail beyond what the schema provides, so the baseline 3 is appropriate.

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 ('Read-only EVM contract call') and names distinguishing traits (decoded revert reason, optional gas estimate). An agent can separate this from siblings like chain_info and chain_state, which read chain metadata rather than execute a contract call.

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 description gives no when-to-use/when-not guidance and never names an alternative. The only conditional hint is 'optional gas estimate' tied to the paid aspect, but there is no explicit instruction on when to choose chain_call over chain_info/chain_state, nor when the paid path is warranted.

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