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

Goes well beyond the annotations by disclosing the cost model ($0.01/call via x402 USDC or card key, first 25 free, failed calls free) and the fact that repeated identical calls are still billed, which explains the idempotentHint=false. The read-only claim matches readOnlyHint=true rather than contradicting it.

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?

Front-loads the resource, the returned fields, and then the when-to-use routing; every sentence is functional. It is dense for one paragraph — the pricing/auth detail competes for attention with the core semantics — but nothing is genuinely superfluous.

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?

There is no output schema, so the description carries the return-value burden itself, and it does so thoroughly while also covering cost, payment path, and safety. An agent has everything needed to decide and call correctly.

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% and the single 'blocks' parameter is already documented as 5-100 with default 20, so the description's repetition of that range and its 'blocks=20' example add little new meaning. Baseline 3 applies when the schema carries the parameter documentation.

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?

Names a specific verb+resource (gas price history on Ink), identifies the underlying RPC method (eth_feeHistory), and enumerates exactly what comes back: base fee in gwei per block, block fullness, and 10th/50th/90th percentile priority fees plus low/average/high over the window.

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?

Gives concrete when-to-use conditions (judge whether fees are rising, pick a priority fee, time a transaction) and explicitly routes the agent to the sibling ink_gas when only the current price is needed.

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