Close financial year

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

Discloses the locking behavior ('locks all dated rows') and error behavior ('returns an error explaining what's unresolved') beyond annotations, which only indicate non-read-only and non-destructive.

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?

Three sentences with no fluff: first states action, second states precondition and error, third recommends prerequisite. Front-loaded and efficient.

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?

Complete coverage: preconditions, behavior, error handling, and parameter sources. No output schema needed; description suffices for correct tool invocation.

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?

Adds meaningful context to parameters: fund_id discovery via whoami or list_funds, financial_year format as label or numeric id from list_financial_years. Schema coverage is 100%, but description enhances usability.

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 clearly states the tool's purpose: 'Close a financial year — locks all dated rows in that year against further edits.' This verb-resource combination is specific and distinguishes it from siblings like reopen_financial_year.

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?

Explicitly states when to use ('Only works once the year is reconciled') and what to do first ('Run reconcile_financial_year first'). Provides clear guidance on prerequisites and error handling.

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