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

Goes well past the annotations: discloses the failure taxonomy (404 for no contract, 422 for non-ERC-20) and that both are uncharged, plus the billing model ($0.01/call, 25 free, failed calls free) and the warning that repeats are not free. It also restates the read-only, non-mutating nature in plain terms where annotations only carry readOnlyHint/destructiveHint flags.

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 what it returns, then usage, then errors and pricing — good ordering with no filler. It is dense and runs long on billing detail, but each clause carries decision-relevant information.

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?

With no output schema, the description names the returned fields (raw amount, decimals, symbol, human-readable amount), the failure modes, and the cost model, which is everything an agent needs before calling. Nothing material is left unstated except the address-format inconsistency noted above.

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%, so the baseline is 3, and the description does add error semantics tied to the inputs. However, 'Both inputs are 0x addresses (40 hex characters)' is misleading: the schema explicitly allows a ticker such as USDC/USDT/WETH/DAI for the token field, and the description's own opening sentence lists tickers. That inconsistency undercuts the parameter guidance it offers.

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 ('ERC-20 token balance of a wallet on Gnosis ... via balanceOf') plus the accepted token universe, and explicitly distinguishes itself from gnosis_balance for the native coin. An agent can pick between gnosis_token_balance, gnosis_token_info and gnosis_balance 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?

Gives the concrete use case ('check stablecoin or token holdings before a transfer or trade') and names the escape hatch for the adjacent case ('for the native coin use gnosis_balance'). The routing condition is stated, not inferred.

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