list_supported_chains_and_tokens

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered structurally. The description adds genuinely non-derivable context: the breadth of coverage (eight chains), that onboarding presets are included, and notably the disclosed 30 bps integrator fee, which an agent could not infer. No mention of caching or response freshness, hence not 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?

One front-loaded sentence with no filler; the most important payload items (chains, token addresses) come first. The hardcoded 'eight' is a slight liability since the count may drift, but the sentence itself is tight.

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?

No output schema exists, so the description correctly carries the burden of describing what is returned, and it does so for a zero-required-parameter listing tool with a fully documented optional filter. It only misses stating that omitting 'chain' returns the full set and how presets map to the onboarding siblings.

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 description coverage is 100% and the single optional 'chain' filter is fully documented there, so the baseline is 3. The description describes only the return payload and adds no meaning about how the chain filter narrows results or what happens when it is omitted.

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 (List) plus a concrete resource set: supported chains, token addresses, onboarding presets, and the integrator fee. This is clearly distinguishable from the sibling quote/onboard/refuel/status tools. It stops short of naming any sibling explicitly, so it lands at 4 rather than 5.

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?

There is no guidance on when to call this versus the onboarding siblings (polymarket_one_click_onboard, hyperliquid_one_click_onboard) that likely consume this data, nor on whether it should be called before quoting or bridging. The listing nature implies a discovery/discovery-first use, but nothing is stated.

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