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

With no annotations supplied, the description carries the full burden and does reasonably well: it discloses the per-call price ($0.001 USDC) and the implicit default chain (base), both of which materially affect invocation. It does not state data freshness/caching behavior or whether the USD estimates depend on external price feeds, leaving a modest gap for a financial-data tool.

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?

Three tight sentences, front-loaded with the use case, then outputs, then chains, then price. The telegraphic fragment style packs a lot in, though the dense comma-separated output list is slightly harder to parse than a short structured sentence would be.

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 single-optional-parameter read tool with no output schema and no annotations, the description covers the essential ground: what you get back, which chains, the default, and the cost. Freshness and return-format details are the only meaningful omissions, and the lack of an output schema means one of those would have been nice.

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 0%, so the description must compensate for the single `chain` parameter. It does: it names all five accepted values and explicitly marks base as the default, information the bare enum in the schema does not convey. Only the absence of any chain-specific caveats (e.g. differing fee models per chain) keeps it from a 5.

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 enumerates exactly what the tool returns — base fee, priority-fee percentiles, EIP-1559 suggestions, block utilisation, and USD cost estimates for transfers, ERC20 transfers and swaps — which clearly separates it from siblings like fx_rates or tx_status. It lacks an explicit verb (it opens with a usage instruction rather than 'Get gas fees'), but the resource is unambiguous.

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?

'Use this before sending a transaction' gives a clear, actionable trigger condition that most agents can act on directly. It does not name when-not-to-use cases or point to an alternative sibling tool, which keeps it short of a 5.

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