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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description goes beyond this by disclosing concrete behavioral nuances: deleted history is excluded, the count is a lower bound on the full first page, feed_stale reflects statement/feed freshness not money-doc activity, and the Xero API cannot see Reconcile-tab statement lines. No contradiction with 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 front-loaded with the primary purpose, followed by usage and caveats. It is slightly repetitive ('Quiet money-docs ≠ dead bank feed' appears twice) and somewhat dense, but every clause carries meaningful information and the Routing section adds structure without bloat.

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 read-only health-check tool with one well-documented parameter, the description covers what data is returned, how to interpret it, and how to distinguish it from related metrics. No output schema exists, but the description provides enough detail about the return contents (last document date, unmatched count, Bank Summary) that an agent can act without missing critical context.

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% and the only parameter (companyId) is fully described in the input schema, including membership requirement. The tool description adds no additional parameter-specific detail, so the baseline score of 3 applies per the rubric for high schema coverage.

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 opens with a specific verb and resource: 'See whether the company's Xero books are posting' and enumerates the exact data returned (money-document date, unmatched document count, Bank Summary). It also explicitly names the sibling it is not ('get_cash_position'), making differentiation clear without needing to open schemas.

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?

Provides explicit when-to-use guidance: 'Use when asked "are the books current?"' and a dedicated Routing section that contrasts this tool against get_cash_position. It also flags a common misconception ('Quiet money-docs ≠ dead bank feed'), which prevents misrouting.

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