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

With no annotations provided, the description carries the full burden. It states the tool returns 'identical data to the paid chain_gas_price tool', which is transparent about the output quality. It also clarifies the free nature. Missing details like rate limits or call constraints, but the simplicity of the tool (0 params) reduces the need. A minor gap prevents a 5.

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 extremely concise with two sentences, front-loaded with 'FREE live sample' to immediately convey key information. Every word serves a purpose without redundancy or 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?

Given the tool has no parameters, no output schema, and a straightforward function (return gas price), the description fully satisfies contextual needs. It explains what the tool does, how it relates to the paid sibling, and its cost model. No missing information for an agent to select and invoke it correctly.

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 has zero parameters, so the baseline is 4. The description does not add parameter information, which is entirely appropriate since no parameters exist. No additional value needed beyond the schema coverage.

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 states the tool provides a 'live sample of the current Base mainnet gas price' with the verb 'sample', specifying the resource (gas price) and network (Base mainnet). It distinguishes itself from the sibling 'chain_gas_price' by highlighting it's free and a preview, making the purpose 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?

The description explicitly says 'FREE live sample' and 'No payment required', and mentions the paid counterpart 'chain_gas_price', which implies when to use this preview version. However, it does not explicitly state when not to use it or provide alternative scenarios, so it falls 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.