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

The annotations already declare readOnlyHint=true, so the read-only nature is known. The description adds useful behavioral context by stating the output is 'in wei (hex string)' and that it is the 'current' gas price, which goes beyond the annotations.

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 only two sentences, with the primary purpose and output format in the first sentence and a use case in the second. It is front-loaded and contains no unnecessary words.

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 simple read-only, zero-parameter tool, the description covers the return format (wei hex string), the target network (Mezo testnet), and the intended use (estimating transaction costs). No output schema exists, but the description is sufficiently complete.

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?

There are zero parameters, so schema coverage is trivially 100%. The description implies no inputs are needed, which is correct. No parameter explanations are necessary, so the baseline of 4 applies.

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 clearly identifies the tool as 'Get current gas price on Mezo testnet' with a specific verb and resource, and it specifies the output format as 'wei (hex string)'. This distinguishes it from sibling tools like mezo_gas_price (mainnet) and eth_gas_price.

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 description provides a clear usage context: 'Use to estimate transaction costs.' However, it does not explicitly mention alternatives or exclusions (e.g., using mezo_gas_price for mainnet), so the guidance is clear but not exhaustive.

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