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

Annotations already cover the safety profile (readOnly, idempotent, openWorld), but the description adds a non-obvious behavioral fact: proof nodes are only counted by default and only returned when include_proof=true, because they are large. That default-return behavior is real value beyond the annotations.

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?

Two dense sentences with the resource front-loaded and no filler. The first sentence is slightly overloaded (field list plus block scoping plus quoted "block"), but every clause carries information.

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 no output schema, the description correctly enumerates the returned values and explains the optional proof-node payload, which is the key thing an agent needs to know. It omits error/limit handling (e.g., behavior when more than 20 slots are requested), but is otherwise complete for this read-only tool.

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 the schema already documents address, block, slots, and include_proof, including the 20-slot cap and default block. The description only restates the include_proof rationale, adding little parameter meaning beyond what is structured.

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+resource — the Merkle proof of an account and its storage slots — and anchors it to a known standard (eth_getProof, EIP-1186). Listing the returned fields (balance, nonce, code hash, storage root, slot values) makes it easy to distinguish from sibling read tools like get_balance, get_code, or get_storage_at.

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?

Explicitly states the intended use: verify state against a block's stateRoot without trusting this server or the node, and explains the include_proof tradeoff. It does not, however, name the sibling alternatives (get_storage_at, get_balance) or state when a plain value read is preferable.

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