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

Annotations already establish read-only/idempotent/non-destructive behavior, and the description adds useful behavioral detail: it filters to saved trips, buckets by start date, reports in each scheme's currency, and embeds trip IDs behind figures. No contradictions 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 main sentence is dense, front-loaded, and contains only relevant information. The trailing 'Pro.' is an unexplained fragment that does not earn its place, but the overall description is still compact and well structured.

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?

With no output schema, the description usefully enumerates the returned figures and their grouping. Combined with complete parameter schema and read-only annotations, an agent has enough to invoke the report correctly; only explicit alternative routing and clarification of 'Pro.' are missing.

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% and every parameter already has a clear description (YYYY-MM formats, scheme enum with default 'all', traveller filter). The tool description adds no parameter-specific meaning beyond this, so the baseline 3 is appropriate.

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 resource (saved trips) and the aggregation dimensions (scheme, calendar month, start date), plus the exact metrics returned (trips, days, subsistence, lodging). This makes it easy to distinguish from sibling tools like perdiem_rates or trip_list.

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 usage context is implied: it is the reporting/aggregation option for trip data, as opposed to listing or calculating rates. However, it never explicitly says when to choose this tool over trip_list, perdiem_calc, or perdiem_rates, and the final 'Pro.' hint is too ambiguous to serve as guidance.

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