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

Annotations already provide readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful output semantics by clarifying that monthly values represent movements, not balances, which prevents misinterpretation of the returned data. It does not disclose behavior such as empty results, error conditions, or output structure, but for a read-only lookup the annotations carry the main burden.

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 short sentences, front-loaded with the core purpose and then a clarifying data-semantics note. No filler, no repetition of the schema, and every sentence adds value.

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?

For a simple by-ID read operation with a clear resource and read-only annotations, the description is largely sufficient. Because there is no output schema, the description usefully names the return content ('ledger and its period movements') and clarifies the monthly-value interpretation. It could go slightly further by describing the shape of the ledger response, but the agent can call the tool correctly with what is given.

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 description coverage is 100%, so all three parameters already have documented meanings. The description adds no parameter-level detail beyond what the schema provides, so the baseline score 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?

Description clearly states a specific verb ('Returns'), a resource ('one nominal account ledger'), and the content ('its period movements'). The emphasis on 'one' helps distinguish it from the sibling brc_get_nom_ac_ledger_by_ids without opening either schema.

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 'one' implies this tool is for a single nominal account, and the sibling name brc_get_nom_ac_ledger_by_ids hints at a plural alternative. However, the description never explicitly states when to prefer this tool or when to choose the by-ids variant, leaving the usage guidance implied rather than stated.

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