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

Adds domain context beyond the annotations by clarifying the balance is for the authenticated account and that calling it does not spend funds — reassuring for a wallet tool where an agent might fear side effects. Annotations already cover read-only/idempotent/no-destroy, so the remaining value is the no-charge guarantee and implicit auth requirement.

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?

Two sentences, front-loaded with the usage trigger and followed by the return value and safety guarantee. No filler or repetition.

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 detail is unnecessary; the description still tells the agent what conceptually comes back (available balance) and that it costs nothing. Currency/account-selection nuance, if any, is left to the output schema.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The schema is empty and closed (additionalProperties false), consistent with the description.

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 a specific verb and resource (get wallet balance) and scopes it to the authenticated SIMcloud account, which clearly separates it from the order/transaction siblings. It stops short of explicitly contrasting with history-type tools, but the resource is 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?

Gives concrete triggering conditions: before a wallet-funded SIMcloud transaction, or when the user asks for their balance. No alternatives or exclusions are named, but no realistic alternative exists among the siblings for a balance read.

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