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

Annotations already mark readOnly/openWorld/idempotent/no-destructive. The description adds meaningful behavioral context: it reads onchain role events, reports controller specificity, centralization, and admin renouncement, and discloses access requirements (pricing, x-credit-token header, no wallet/API key). No contradiction with 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?

Every sentence contributes: the purpose question, sibling contrast, data source and outputs, use case, input reminder, and access/cost. It is longer than minimal but justified by the amount of useful context; minor redundancy with schema's required-address note keeps it from a 5.

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?

For a single-parameter read-only audit tool with a full output schema and safety annotations, the description supplies everything an agent needs: what it reports, when to use it, what input it expects, and how to access it. No important gaps.

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?

The only parameter, address, is fully described in the schema as 'B20 token address' (100% coverage). The description reiterates 'Required input: address' and contextualizes the target as 'this B20', but adds no format or syntax detail, so it stays at baseline 3.

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 ('Reads the token's role-based access control... reports the exact controllers'), a specific resource (B20 token roles), and immediately distinguishes from sibling b20_safety ('WHICH powers' vs 'WHO holds them'). The opening question 'WHO can mint, seize, freeze or pause this B20?' makes the purpose unmistakable.

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?

Explicitly contrasts with b20_safety, telling an agent to use this when it needs WHO holds powers rather than WHICH powers exist. Also gives a concrete trigger: 'The issuer-control map an agent needs before holding a regulated Base-native asset.' This provides clear selection criteria.

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