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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds genuine scope framing beyond them — it is a decision aid, not an outage monitor or executor, and operates on a bounded set of chains. It omits any rate-limit or data-freshness note, so it falls short of 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?

Front-loaded with purpose, then routing guidance, then explicit exclusions; every sentence carries routing value. 'Helps choose the optimal chain for transactions' is mildly redundant with 'when selecting a network for an action', keeping it from a perfect score.

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 no explanation, and annotations carry the safety profile. Purpose, usage, and disambiguation against oracle.chain_status and gas.tracker are all present — nothing needed to invoke 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 'chains' parameter is fully documented in the schema with the enum list and maxItems. The description only restates the 'bounded set' constraint, adding little syntax or meaning beyond the schema, so the baseline 3 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?

States a specific verb (compare) and resource (EVM chains), and enumerates the compared dimensions (gas costs, block time, best DeFi yields). An agent can distinguish this from siblings like chain.health or gas.tracker 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?

Explicitly says when to use it ('compare a bounded set of EVM chains when selecting a network for an action') and when not to ('not an outage monitor or transaction executor'), naming the correct alternatives (oracle.chain_status for availability, gas.tracker for a live quote).

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