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: read-only scope, five-chain support, exact return shape (raw 32-byte plus asUint, decode it yourself), and operational/cost traits (no API key, no rate limit, $0.005 per call paid over x402 in USDC). These are precisely the traits an agent can't infer from the schema.

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?

Front-loaded with the triggering condition, then the exclusion list, then cost/access notes — a well-ordered four-sentence block with no filler. The first sentence is densely packed (behavior, chains, return shape) and would read better split, which keeps it just short of a 5.

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?

No output schema exists, yet the description explains what comes back (raw 32-byte result plus asUint) and that decoding is the caller's job — the key completeness gap for an escape-hatch tool. Payment and rate-limit conditions are also covered, leaving nothing an agent needs before calling it.

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 coverage is 100%, so `to`, `data`, `from`, `block`, and `chain` are already documented by the schema. The description confirms the calldata-encoding expectation and the five-chain scope but adds no format, selector, or block-tag guidance beyond the schema; 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: runs any read-only call with your own calldata on five chains and returns the raw 32-byte result plus asUint. It explicitly positions itself against the sibling family of typed routes (evm_balance, evm_erc20_balance, evm_nft_owner, evm_token_info), so an agent can distinguish it without opening any 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 an explicit selection rule ("Use when an agent needs a contract value that none of the typed routes covers") and an explicit exclusion list ("Do not use for balances, allowances, token data or NFT owners"), naming the alternative behavior in each case. It also frames itself as "the escape hatch, not the first choice," which is a clear priority signal.

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