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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds real context by disclosing that data comes from public website HTML (a scraped source, implying volatility) and that rows are normalized; it does not mention pagination or the limit ceiling, but that ceiling is in the schema.

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?

A single front-loaded sentence with no filler; the resource and source are stated immediately and every clause earns its place.

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 explained, and the annotations carry the safety profile. For a simple two-parameter listing tool the description is nearly sufficient, with the only gap being routing vs. coingecko_chain.

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%, with limit and vs_currency both documented including the full currency enum, so the baseline of 3 applies. The description adds nothing about parameter behavior, format, or defaults beyond what the schema states.

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 (returns) and resource (normalized chain rows) plus the exact source (/en/chains), so an agent knows it is a chains listing. However it does not differentiate itself from the sibling coingecko_chain (singular), leaving ambiguity about list vs. single-chain detail.

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?

No explicit when-to-use guidance, no prerequisites, and no mention of the closely related coingecko_chain tool. The agent must infer that this is the bulk-listing variant from the plural 'rows' alone.

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