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

With no annotations, the description carries the burden well: it discloses that a 20% buffer is applied and that the call 'fails clearly when the call would revert', which is exactly the kind of behavioral detail an agent needs. It does not say whether the estimate is simulation-based/off-chain read-only or whether results vary by from_address/chain RPC, leaving some gaps.

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?

A single dense sentence ordered by importance: what is computed, the buffer caveat, the failure mode, then the usage trigger. No filler or restatement of the title.

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?

An output schema exists, so return-format explanation is unnecessary, and the description covers the estimate, the 20% buffer, and revert behavior. It omits whether from_address materially changes the estimate or whether chain affects which RPC is used, which are the remaining ambiguities for a 5-parameter tool.

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% across 5 parameters and the description never addresses to, data, chain, value_eth, or from_address directly. It partially compensates by naming eth_estimateGas, letting an Ethereum-literate agent map the familiar to/data/from/value fields, but that inference is left implicit.

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 names a specific verb and resource ('Estimate the gas a transaction will use') and anchors it to the underlying RPC method (eth_estimateGas), plus states the secondary output (cost at current gas price). This clearly separates it from gas-price-only siblings like evm_gas_fees, though no sibling is named explicitly.

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 before signing' gives a concrete precondition/context for calling the tool. There is no guidance on when NOT to use it (e.g. for a revert-free dry run or for network-level fee data, where evm_gas_fees would be the alternative), so it stops short of full routing guidance.

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