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

Annotations already declare read-only, open-world, and non-idempotent behavior, but the description adds meaningful context beyond them: it specifies a single `eth_gasPrice` JSON-RPC call, explains that live results may change between calls (justifying non-idempotency), and explicitly states it does not estimate total cost, submit transactions, or authorize execution.

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 purpose and well-organized into USE WHEN / DO NOT USE WHEN blocks. There is minor redundancy between 'for transaction planning' and the later 'before estimating fees or preparing a transaction,' but overall it is efficient.

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-parameter read tool with an output schema and rich annotations, the description covers purpose, usage boundaries, alternatives, and behavioral limits. Nothing needed to call it correctly is missing.

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 `chain` parameter has a clear enum and description. The tool description mentions 'Ethereum or Base' but adds no syntax or format details beyond what the schema already provides, so the baseline of 3 is appropriate.

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 verb and resource ('Retrieve the current gas price for Ethereum or Base') and explicitly scopes it to transaction planning. It clearly distinguishes itself from the named sibling tools for transaction inspection and wallet balance.

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?

Provides explicit 'USE WHEN' and 'DO NOT USE WHEN' sections with named alternatives (`evm_transaction_hash_lookup`, `evm_wallet_balance_lookup`) and the conditions that select each. Nothing is left to inference.

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