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

No annotations provided and the description is tautological, disclosing nothing about behavior — e.g., whether it queries a chain RPC, what network defaults apply, whether it returns the latest block number or a historical one, or what happens with an invalid chain.

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?

The description is a one-sentence repetition of the tool name with no useful content. This is not concise communication — it is missing substance entirely.

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?

The tool takes a chain parameter and is surrounded by dozens of blockchain-related siblings (x402-chain-id, x402-gas-price, x402-block-fee), yet the description gives no indication of what block metadata is returned, what parameters matter, or how it differs from related tools. Inadequate for reliable agent selection.

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%, but the only parameter description is the generic "Chain to process" — it does not explain valid formats (name, ID, chain key), whether "chain" can be omitted (no required parameters), or which chains are supported. The description adds nothing beyond the schema.

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?

Description is "Block Number: Block Number" — a pure tautology that restates the tool name with no verb, resource, or behavioral detail. It does not distinguish this from any of the thousands of sibling tools.

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?

No guidance on when to use this tool versus alternatives like x402-block-fee, x402-chain-info, or x402-erc20-info. The name implies it fetches a block number, but the description provides no context or exclusions.

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