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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior, so the bar is lower. The description adds substantial operational context: dual independent RPC verification, a divergence report, free public RPCs with no key, and a per-call cost in USDC on Base via x402. This goes well beyond what annotations convey.

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 front-loaded with the core value proposition and verification approach. It is slightly redundant by stating the $0.03 USDC x402 Base cost twice, which keeps it from being fully tight.

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 read-only multi-chain gas oracle with no output schema, the description covers what the tool returns (gas price per chain and divergence report), which chains are included, the verification method, and payment requirements. Annotations handle safety, so no critical gap remains.

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 value by enumerating all five supported chains (ethereum, base, arbitrum, optimism, polygon), whereas the schema example only shows 'base', helping the agent populate the single input parameter correctly.

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?

States a specific resource (gas price across five named chains) and a distinctive verification method, so the agent can tell it provides multi-chain gas data. It does not explicitly distinguish itself from siblings like bitcoin_fees, so it falls short of a 5 under the calibration.

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 phrase 'dual-verified is what you time transactions with' implies a usage context for transaction timing, and 'Free public RPCs, no key' gives a reason to prefer it. However, no explicit when-to-use, when-not-to-use, or alternatives against siblings are provided.

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