vendor_spending_report

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

With no annotations provided, the description carries full burden and does well: it states the tool reads posted vendor bills, implies read-only behavior, describes the default return format (compact aligned text table), and explains the verbose and group_by behavioral variations including that group_by 'Overrides verbose'. This is strong behavioral disclosure for a reporting tool.

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 well-structured with an intro summary, blank-line-separated sections, and a clean Args list with each parameter on its own line. It's appropriately detailed for a tool with 5 parameters and 0% schema coverage, though slightly verbose with the group_by explanation.

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?

Considering the output schema exists (which relieves the description of explaining return values), no annotations, and 0% schema coverage, the description does well covering purpose, behavior, parameter semantics, and format toggles. It could add more context about what 'posted' means or prerequisites (e.g., bills must be posted first), and there's no mention of potential errors or date range limits, leaving minor gaps.

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 0%, so the description must fully document all 5 parameters to compensate. It does document each parameter (start_date, end_date, vendor_id as optional filter, verbose, group_by with its month/quarter/year values and behavior). However, it partially compensates — the descriptions add real semantic meaning (date formats, what group_by does, override behavior). Given 0% schema coverage, this is a significant contribution, but I'll rate it lower because the parameter explanations, while present, are brief and don't fully elaborate on formats or edge cases.

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 'Get spending breakdown by vendor for a period' with a specific verb+resource and then details what it analyzes (posted vendor bills showing total billed, total paid, and outstanding amounts). It effectively distinguishes itself from similar reporting siblings like spending_by_category and get_budget_report by focusing on per-vendor bill analysis.

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 explains when to use it (reporting period vendor spending) and documents the verbose and group_by toggles that change output format. However, it doesn't explicitly state when NOT to use it or name alternatives, though the tool's purpose is fairly distinct among a large sibling list.

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