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

No annotations are provided, so the description carries full burden. It discloses a key behavior: a payment of $0.001 USDC is required via x402. However, it does not address other behavioral aspects such as idempotency, rate limits, or whether the snapshot is real-time or cached. The payment disclosure is valuable but incomplete.

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 sentences deliver the essential purpose and a critical constraint (payment). No unnecessary words. The structure front-loads the core function and appends the cost as a succinct second sentence. Every word 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 tool with no parameters and no output schema, the description adequately covers returns (block height, gas price, network) and a key constraint (payment). It does not specify whether the data is current or historical, or describe the response format, but the core functionality is sufficiently captured for most use cases.

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 tool has zero parameters and 100% schema coverage, so no input parameter documentation is needed. The description compensates by listing the output fields (block height, gas price, network), which indirectly informs the agent about what to expect. This adds value beyond the empty schema, meeting the baseline for parameterless tools.

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 it provides a 'Base mainnet chain snapshot' with specific data (block height, gas price in gwei, network). This distinguishes it from sibling tools like crypto_price or dns_lookup, which are unrelated. The verb 'snapshot' implies retrieval, making the purpose unambiguous.

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 description implies use when Base mainnet chain data is needed, but provides no explicit guidance on when to prefer this tool over alternatives, nor any exclusions or prerequisites. The payment detail hints at a cost constraint, but it's not framed as a usage rule.

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