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

Annotations already declare non-read-only, non-idempotent, non-destructive, closed-world. The description adds real value beyond that: it discloses that a snapshot is persisted and can be compared against later, and that dry_run is a no-write path. It does not explain what happens on a second close of the same month, despite idempotentHint=false, nor any permission or 'Pro' tier requirement implied by the trailing token.

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?

Very compact: the artifacts and the snapshot consequence are front-loaded, then the dry_run caveat, then a licensing flag. Nothing meaningful is padded. Points off only for the telegraphic single-sentence construction and the unexplained 'Pro.' fragment, which reads as leftover metadata.

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 mutating, non-idempotent close with no output schema, the description covers what gets written and the dry-run escape hatch, which is the essential shape. It leaves open the re-close/overwrite semantics and any response details, and the 'Pro' suffix is not decoded into a prerequisite an agent could act on.

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%, so the schema already documents month format, dry_run default, and the currency rule about periods holding multiple currencies. The description only restates dry_run's no-write behavior, which the schema's own field description already covers, and says nothing about currency. Baseline 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 the concrete artifacts produced: unposted/unbalanced exceptions, trial balance, bank reconciliation, plus a stored close snapshot with later drift detection. That distinguishes it from the read-only sibling trial_balance and from period_delete. It stops short of 5 because the core verb is expressed obliquely ('List what a month leaves... then store the close') rather than stated outright, and the trailing 'Pro.' is unexplained noise.

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?

It gives one useful selector: 'dry_run writes nothing', which signals a preview path before committing. It also implies a two-call workflow (close now, later call to check drift) without saying how to trigger that check. No alternatives are named, so an agent gets no explicit direction to period_delete or trial_balance.

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