cash_register_balance

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

Annotations already establish this as a read-only, idempotent, non-destructive, closed-world read. The description adds genuine value beyond that by documenting a failure/degenerate return: '{ configured: false }' when no cash-type bank account exists or its opening balance is unset, which an agent would otherwise misinterpret as an error or empty result. It stops short of describing pagination or freshness/latency guarantees.

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 tight sentences: the payload contents come first, the degenerate-case return second. Every clause carries information an agent would otherwise have to discover by calling the tool.

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 bears the burden of explaining return values, and it does so by enumerating the returned fields and spelling out the { configured: false } shape. It does not cover units/currency of the amounts, which is the main remaining gap for a monetary tool.

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?

There is only one optional parameter and schema coverage is 100%, so the schema already fully documents companyId as a UUID override defaulting to the active company. The description adds nothing about the override or its fallback behavior, so the baseline of 3 applies.

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 names a concrete resource (the till / cash register) and precisely enumerates what the snapshot contains: opening balance, cash in/out since opening, manual movements, current balance. This clearly separates it from the movement-listing siblings (cash_register_movements_list) and the ledger tool, though it never names those siblings explicitly.

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 word 'live snapshot' implies a point-in-time read as opposed to a historical listing, which hints at when to prefer this over cash_register_ledger or cash_register_movements_list. However, there is no explicit statement of when to use this tool, when not to, or which sibling to pick for historical detail.

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