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

The description adds the behavioral detail of batching into a single RPC call and describes the fee history as bounded, which supplements annotations like readOnlyHint and idempotentHint. It does not contradict the annotations and provides performance-relevant context beyond the structured fields.

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 entire description is one compact sentence of about 22 words, front-loaded with the core action ('Read the latest Base mainnet block') and includes no redundant words. Every part adds useful 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?

Given that an output schema exists and both parameters are fully documented, the description is sufficient to understand the tool's purpose and expected output. It mentions the key data components (block, fee history, gas utilization, percentiles) and does not omit critical information for an agent deciding to call it.

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 provides complete descriptions for both parameters (fee_history_blocks and reward_percentiles), covering 100% of parameters. The description's mention of 'bounded' and 'priority-fee percentile samples' loosely maps to these parameters but does not add substantive meaning beyond the schema, 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 reads the latest Base mainnet block and an EIP-1559 fee history in a single RPC batch, with specific data points like gas utilization and priority-fee percentiles. This verb+resource structure distinguishes it from sibling tools like crypto.base-block-inspect, which inspect individual blocks.

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 gives clear context for when to use the tool—to get a quick status snapshot of Base network's latest block and fee market in one call. However, it does not explicitly mention alternatives or exclusions, making it a 'clear context, no exclusions' case.

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