Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations cover safety (readOnly, idempotent, openWorld, non-destructive), and the description adds real behavioral depth beyond them: balances come from the lane the collateral settles on (committed ledger balance batched to Base vs onchain ERC-20 balanceOf), and values are raw integer strings in native decimals requiring division by 10^decimals.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.