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

With no annotations, the description carries the full burden. It usefully reveals that the tool returns base fee plus priority fee for historical blocks and that free usage is limited to 5 trial calls per signed wallet, adding auth/quota context. However, it does not disclose output format, input requirements, or behavior with missing parameters.

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 short, front-loaded with the main purpose, and every sentence adds information. The 'Fee History:' label mildly repeats the tool name, but the rest is efficient and scannable.

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?

Despite low apparent complexity, the tool has four optional string parameters with generic descriptions and no output schema or annotations. An agent has no guidance on which parameters are needed, what formats chain/network expect, what defaults apply, or what the response shape looks like. This is insufficient for confident invocation.

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 description coverage is 100%, so the baseline is 3. The description adds only marginal meaning by linking 'N' to block count, but it does not clarify the confusing relationship between 'n' and 'blocks', nor accepted formats for 'chain' and 'network'. The parameter descriptions remain generic placeholders.

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's resource and output: fee history for the last N blocks with base fee and priority fee. It is clear enough to distinguish from single-block or current-fee tools like x402-block-fee, though it lacks an explicit verb and does not directly name sibling alternatives.

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?

There is no explicit guidance on when to use this tool versus related tools such as x402-fee-estimate, x402-gas-price, or x402-block-fee. The free-trial note hints at access constraints but provides no decision context for selecting this tool over alternatives.

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