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

With no annotations, the description carries the disclosure burden and does well: it names the two upstream RPC methods, gives a concrete input-to-output example, and states the price ($0.001 USDC). It omits failure behavior (unreachable RPC, unknown chain name) and whether results are cached, which keeps 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?

A single front-loaded sentence covering purpose and provenance, followed by an example and a price. Every element earns its place and nothing is padded.

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 trivial single-value lookup with no output schema, the description supplies the return shape via example and the cost, which is enough to invoke it confidently. The unresolved gap is the optional 'chain' parameter and what a missing value yields.

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 0% for the single 'chain' parameter, so the description must compensate. The example {chain:"base"} → {chain_id:8453} usefully shows that a human-readable chain name is accepted rather than a numeric ID, but it does not enumerate valid values or explain the behavior when 'chain' is omitted (the parameter is not required).

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 resource (EIP-155 chain ID) and how it is obtained (eth_chainId + net_version), and its scope is clearly distinguishable from siblings like chain_network_info or chain_block_number. An agent can tell exactly what this returns without opening the 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?

The phrase 'confirm which network you are about to sign on' supplies a concrete usage context that implies when to call it (pre-signature verification). It stops short of naming an alternative or stating exclusions, so the routing guidance is clear but not explicit.

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