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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real context the annotations don't: the data is static on-chain metadata (supply, decimals) and the call is 'Free', implying no cost or quota. It does not say what happens on lookup failure or how stale the supply figure is.

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 the resource and the returned fields, then three short disambiguating clauses with zero filler. The telegraphic fragments ('Free.', 'Not a reserve check.') read slightly clipped but each earns its place.

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 must characterize the return value, and it does by enumerating the four field groups. It leaves implicit that omitting the optional coin parameter returns all nine stablecoins, which is inferable from the opening clause but not stated.

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% and the schema already lists the ticker enum and the 'or its address' fallback, so the description adds no new parameter meaning. Baseline 3 applies because the schema does the heavy lifting.

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?

Names the specific resource (Keeta's nine $KB stablecoins) and enumerates the exact fields returned: address, decimals, on-chain supply, and currency-map/anchor-metadata listing status. The clauses 'Token amounts, not prices' and 'Not a reserve check' sharply separate it from pricing and reserve tools.

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?

Provides clear negative guidance that routes the agent away from wrong siblings ('Not a reserve check', 'Token amounts, not prices'), which implies using get_price/quote_* tools for prices. It stops short of naming the positive alternative explicitly, so a 4 rather than a 5.

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