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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description still adds real value: the exact semantics of the confidence percentage, an enumeration of the exception categories returned, and the default-period behaviour. It also instructs the agent to surface the returned message, which is non-obvious behavioural guidance not captured in any structured field.

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?

Front-loaded with the purpose and return metric, then triggers, then defaults and follow-up behaviour — a logical order with no filler. The exception-category list is slightly long but each item is a distinct return field, so it earns its space.

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 and no required parameters, the description fully carries the burden by explaining what the response contains (confidence percentage plus five exception categories) and what an agent should do with it. Nothing needed to invoke or interpret it is missing.

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?

Both parameters are fully documented in the schema (coverage 100%), including defaults and the list_companies pointer, so the description need not compensate. The description only restates the default month behaviour, adding no syntax or format detail beyond the schema, making baseline 3 appropriate.

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?

States a specific verb and resource ('Check how closed a month's books are') and immediately defines the returned metric as a close-confidence percentage with its exact computation. However, it does not differentiate itself from the sibling 'month_close_summary' or 'get_reconciliation_status', which an agent would plausibly confuse it with.

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 trigger phrasings ('is my month done?', 'month-end') plus a default ('last complete month'), which is strong usage context. It stops short of naming when NOT to use it or routing to alternatives like month_close_summary, so no exclusions are stated.

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