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

With no annotations, the description carries full behavioral burden. It discloses key transformation rules (income→turnover, expenses→operating costs, owner top-up excluded) and the signed-major-units convention. It stops short of describing error behavior, unknown-category handling, or output format, which prevents a 5.

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 with no filler. The action is front-loaded, and each clause adds either a rule or a reference. Every word 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?

The description thoroughly covers input format and mapping rules, but with no output schema it does not specify the structure of the returned balance sheet figures or error cases. For an agent to consume the result downstream, the return format would need to be known, so completeness is adequate but not full.

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 already describes the totals object with sign, units, and an example. The description restates that but adds the cross-reference to categorise_transactions for obtaining codes, a small value-add. 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?

The description states a specific transformation ('Turn categorised bank-statement totals into balance sheet figures') and enumerates the rules that define its behavior, making it clearly distinct from siblings like categorise_transactions (source of codes) and dormant_figures (different purpose).

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 after categorise_transactions by telling the agent to get codes from that tool, and the context of producing balance sheet figures indicates a later stage in the pipeline. It does not explicitly mention alternatives or when not to use it, but the usage context is clear enough.

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