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

Annotations already cover read-only and non-destructive behavior, but the description adds genuinely new context: pricing ($0.01/call, first 25 free, failed calls free), a 422 uncharged error for non-ERC-20 addresses, and the note that repeats are charged — which reconciles the otherwise surprising idempotentHint=false. It does not describe latency or caching, but for a single-address read that is minor.

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 usage, then input format, then pricing — a sensible order with no filler sentences. It is on the long side for a one-parameter tool, but every sentence carries operative information (cost, error case, no side effects).

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?

There is no output schema, and the description compensates by naming the four returned fields, plus error behavior and billing. For a one-parameter read tool, an agent has everything needed to call it and interpret the result.

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 schema already explains the ticker-or-address duality, so the baseline is 3. The description goes further with a worked address example and the failure semantics of an address that is not an ERC-20 contract (422, uncharged), which materially helps the agent pass a valid value.

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 ('Look up the name, symbol, decimals and total supply of an ERC-20 token contract on Gnosis') and even names the exact return fields. It explicitly separates itself from the sibling gnosis_token_balance, so an agent can choose without opening either 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 two concrete use cases ('identify an unknown token address', 'format raw amounts') and an explicit exclusion routing holder balances to gnosis_token_balance. Nothing about when to pick this vs. alternatives 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.