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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely non-structured context: the x402 payment model on Base, the $0.02 per-call price, the prepaid x-credit-token header for unlimited calls, the absence of a free tier, and no API key requirement — all auth/cost details the agent cannot get from annotations.

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?

Purpose is front-loaded in the first clause and the description is dense rather than padded. The em-dash fragments and payment boilerplate add length, but every sentence carries information relevant to calling the tool.

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-shape explanation is unnecessary, and the description still supplies payment/auth requirements, the balance-scaling interpretation, and the stablecoin edge case. The main omission is sibling routing, which would be needed for an agent choosing among the many b20_* tools.

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?

Only one parameter, fully described in the schema ('B20 token address') at 100% coverage, so the schema does the work. The description restates that address is required but adds no format, checksum, or chain details beyond what the schema already provides.

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: reads a B20 Asset token's rebase multiplier, with a clear secondary purpose of flagging whether holder balances are being scaled. It partially differentiates from siblings by noting stablecoin variants return no-rebase, though it never names the closest sibling (b20_rebase_history) that an agent might confuse it with.

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?

Usage is implied (checking whether an issuer is scaling balances through rebase) but there is no explicit when-to-use or when-not-to-use guidance, and no routing to b20_rebase_history, b20_supply, or b20_stablecoin. The stablecoin aside hints at scope boundaries but is framed as a return-value fact rather than a selection rule.

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