base_fee

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

With no annotations, the description carries the full burden. It discloses the chain, the unit, and the fact that the value is a live estimate rather than a fixed constant, but says nothing about staleness, caching, refresh cadence, or what limits apply — relevant for a fee oracle whose value moves block to block.

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?

One sentence, front-loaded with the resource and unit before the intended use. Every clause earns its place; there is no filler.

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 zero-parameter read tool with no annotations and no output schema, the description supplies the essentials: what is measured, the unit, and the purpose. It stops short of saying whether the return is a single number or a breakdown by speed tier, which matters when costing a payment.

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 takes zero parameters, so the baseline is 4. There is nothing for the description to disambiguate on the input side, and it correctly spends no words doing so.

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 (Base L2 gas fee), a concrete unit (gwei), and the value it represents (current estimate). The description resolves the ambiguity of the bare name 'base_fee' and cannot be confused with any of the unrelated siblings (iss, earthquakes, weather, postcard, spend_status, risk_brief).

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?

"For costing x402 payments before making them" gives an explicit when-to-use trigger, which is exactly the decision an agent needs. No alternatives or exclusions are named, but no sibling tool plausibly competes for this job, so the omission is low-risk.

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