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

Annotations already cover readOnly, idempotent, and non-destructive behavior. The description adds meaningful context beyond annotations: deleted documents are excluded, results are newest-first with 100 per page, and Xero's Accounting API does not expose the Reconcile queue. This gives the agent a clear behavioral model without contradicting the annotations.

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?

The description is information-dense and front-loaded: the first sentence contains the core purpose, followed by exclusions and guidance. The 'Routing:' line is slightly redundant with the earlier 'NOT' clarification, but overall every sentence contributes.

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 list tool with annotations covering safety and idempotency, the description is sufficiently complete. It covers scope, ordering, pagination, exclusions, and an alternative for failure detection. The absence of an output schema is acceptable because the tool's purpose and result shape are clearly implied.

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 baseline is 3. The description adds context about pagination order and page size ('newest first, 100 per page'), which helps interpret the page parameter, but it does not add significant meaning to companyId beyond what the schema already provides.

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 verb and resource: 'List authorized, unreconciled Xero spend/receive MONEY DOCUMENTS (deleted documents excluded), newest first, 100 per page.' It clearly distinguishes itself from the Reconcile-tab bank-statement queue and from sibling tools like list_xero_bank_transactions and get_xero_books_health.

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 explicitly says when to use it: 'Use to see which books documents are still unmatched.' It also provides an alternative: 'Use get_xero_books_health if the feed looks frozen.' The negative guidance about the Reconcile tab prevents misuse.

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