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

Annotations already establish read-only/idempotent/non-destructive behavior. The description adds useful context beyond that: results are grouped per currency, include gross/net/VAT, and are never mixed, plus the receipts-only scope. 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?

Two tightly written sentences, front-loaded with the core purpose and immediately followed by the key scoping caveat. Every clause earns its place.

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 summary tool, the description covers the essential behavior, grouping dimensions, currency handling, and the receipts-only constraint. Minor gaps remain around the optional project/billable filters and the exact response format, but nothing that prevents correct 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?

The schema already documents from, to, and group_by, and the description reinforces group_by's allowed values. However, the optional project and billable parameters have no descriptions in the schema or the tool description, so those remain underspecified.

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 clear verb and resource: totals for a date range, grouped by category/project/month/merchant. It also differentiates from bank-statement totals, so an agent can tell it apart from related tools without opening the schema.

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 explicitly scopes the tool to receipts and names the alternative for bank transactions (statement_summary). It does not spell out when to prefer expense_list or expense_export, but the summary-vs-list distinction is reasonably clear from context.

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