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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is well covered. The description adds valuable operational behavior: the $0.02 cost per call, the x-credit-token header for unlimited calls, the 1 free call/day per tool, and the explicit statement that no wallet or API key is required. This goes well beyond the annotations and gives an agent concrete expectations about auth, rate limits, and cost.

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?

The description is front-loaded with the core purpose and field list, then moves to operational details like pricing and auth. It is reasonably compact for the amount of information conveyed. There is minor redundancy in 'Full profile... Complete B20 token profile,' but it does not seriously hurt readability.

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 tool with an output schema, the description covers the essentials: what data is returned, what input is required, the data source, pricing, auth requirements, and the relationship to b20-safety. The main gap is the lack of explicit routing among the large family of b20_* data tools, but this is a minor weakness given how clearly the scope is defined.

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 schema already provides 100% coverage for the single 'address' parameter with the description 'B20 token address.' The tool description merely repeats 'Required input: address' without adding format, chain, or example-level detail. With complete schema coverage, the baseline of 3 is appropriate.

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?

The description clearly opens with 'Full profile of a Base-native B20 token' and itemizes the exact fields returned: variant, name, symbol, decimals, total supply, supply cap, transfer policies, pause states, and rebase. It also positions itself as 'The data companion to b20-safety,' which distinguishes it from at least that sibling. However, it does not explicitly differentiate itself from other closely related data tools like b20_metadata, b20_supply, or b20_dossier.

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?

The description implies usage as the data counterpart to b20-safety and states that only an address is required, but it never gives explicit when-to-use or when-not-to-use guidance relative to the many overlapping b20_* sibling tools. No alternatives besides b20-safety are mentioned, and there is no exclusion such as 'for safety assessment use b20_safety instead.'

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