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

Annotations already declare readOnly=true, idempotent=true, destructive=false and openWorld=true, so the safety profile is covered. The description adds genuine behavioral context beyond that by disclosing the shape of the returned data per chain family (base fee, priority fee, predictions for EVM; priority fees, TPS, congestion for Solana). It stops short of stating freshness/latency or rate-limit behavior, so it is not a full 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?

Four tight sentences, each earning its place: capability, per-chain payload, scope trigger, then exclusions. Front-loaded with the verb+resource and no redundant restatement of the title or schema.

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 values need not be described, and the description instead supplies the routing context (scope plus the three sibling exclusions) an agent needs to call it correctly. Nothing material is missing for a single-parameter read 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?

Only one parameter (chain) and schema description coverage is 100%, with a fully enumerated set of values and a documented EVM/non-EVM split, so the schema carries the semantics. The description restates the EVM vs Solana distinction but adds no new per-parameter meaning, which is the baseline-3 case.

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 (get current gas/fee data) and immediately scopes what the payload contains per ecosystem (EVM base/priority fee/predictions; Solana priority fees/TPS/congestion). It explicitly names the sibling tools it is not, so an agent can distinguish it from gas.history, gas.predict and gas.optimize without opening any schema.

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?

Gives an explicit trigger phrase ("what are fees now?") and then enumerates the excluded use cases with their correct alternatives: historical series -> gas.history, short-horizon forecast -> gas.predict, timing advice -> gas.optimize. This is exactly the when/when-not/alternative structure that removes routing ambiguity.

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