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

Annotations already establish readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavioral framing by labeling itself a decision aid rather than a monitor or executor, which prevents misuse. It stops short of describing comparison recency or data-source freshness.

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?

Three sentences, front-loaded with the comparison scope before the routing guidance. The middle sentence ('Use to compare a bounded set of EVM chains when selecting a network for an action') partially repeats the opening sentence's scope, a minor redundancy in an otherwise tight definition.

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-value detail is not owed here. Between the stated dimensions, the usage boundaries, and the named alternatives, an agent has everything needed to decide when and how to call this 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?

With one parameter and 100% schema description coverage, the schema already documents the chain enum, the default set, and the maxItems cap. The description's only added signal is 'bounded set of EVM chains', which restates the maxItems constraint the schema already encodes. Baseline 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+resource ('side-by-side comparison of EVM chains') and enumerates the compared dimensions (gas costs, block time, DeFi yields). It explicitly contrasts itself with chain.health, gas.tracker, and oracle.chain_status, so an agent can route without opening a sibling 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 when ('selecting a network for an action') and explicit when-not ('not an outage monitor or transaction executor'), naming three alternative tools for adjacent needs. 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.