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

With no annotations provided, the description carries the burden. It discloses that this is a 'Live public RPC' and a 'paid call,' which are behavioral traits. It also frames it as a 'freshness read,' implying a read-only operation. However, it doesn't detail error behavior, rate limits, or response format.

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?

Three concise sentences, front-loaded with the core function, then use case, then cost/RPC details. Every sentence earns its place.

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 simple read tool with one documented parameter, the description provides the method, supported chains, use case, and cost. It lacks an explicit response format, but the standard eth_blockNumber method implies a hex block number; still, given no output schema, a bit more detail could help.

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 input schema already documents the single parameter (x_payment) with 100% coverage. The description adds no additional parameter semantics, so baseline 3 applies.

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 clearly states the tool returns the current chain tip (latest block height) via eth_blockNumber across multiple chains, distinguishing it from sibling tools like chain_block_header or chain_confirmations.

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 identifies the usage context: 'The freshness read settlement, indexing and trading agents poll to know where the chain is.' This implies when to use it, but it doesn't explicitly exclude alternatives or name sibling tools.

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