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

The description provides detailed behavior not captured in annotations: the exact currency resolution rules (explicit > single wallet > most recent task), the absence of a stale USD default, the meaning of each of the four balance numbers, and the per-task locks array. Annotations already declare read-only and idempotent, and the description does not contradict; it adds crucial context about the response semantics.

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 organized with clear sections: purpose, currency resolution, field definitions, locks array, usage context, and alternative. Despite being longer than average, every sentence adds essential information about balance semantics that the agent needs. The priority ordering is front-loaded and each sentence 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?

Given there is no output schema, the description fully explains the structure and meaning of the response, including the locks array field names. It also covers when to use the tool, authentication, and the relationship between balance components. This is complete for an agent to select and invoke correctly.

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%, so baseline is 3. The description elaborates on the currency parameter's default resolution logic and explicitly says omitting currency uses smart default, adding meaning beyond the schema. The apiKey parameter is sufficiently described in the schema, so no further description is needed.

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 opens with 'Get your wallet balance for a specific currency,' clearly stating the verb and resource. It distinguishes itself from the sibling tool list_wallets by explicitly directing 'For all currencies at once, use list_wallets.' The scope is precise and unambiguous.

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?

It explicitly states 'Use this before fund_task to verify you have sufficient available funds,' giving a concrete when-to-use scenario. It also names the alternative for all currencies (list_wallets), which directly addresses tool selection.

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