vendor_spending_report

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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial behavioral context: it analyzes only posted vendor bills, defaults to a compact aligned text table, switches to structured JSON with verbose, and changes output shape when group_by is set. 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 purpose, then delivers param semantics in tight bullet-like Args lines. Every sentence adds value; there is no filler or repetition of schema fields without added meaning.

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 report tool with an output schema present, the description covers data source, output formats, default behavior, override behavior, and all parameter semantics. Nothing an agent needs to decide whether to call it or how to invoke it correctly is 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 description coverage is 0%, and the description fully compensates. It documents the YYYY-MM-DD format for date parameters, the optional vendor_id filter, the verbose boolean with its exact output implications, and group_by's allowed values and override behavior. Every parameter is meaningfully explained beyond the bare schema.

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: 'Get spending breakdown by vendor for a period.' It then defines the exact metrics (total billed, total paid, outstanding amounts) and the data source (posted vendor bills), making it clearly distinct from siblings like spending_by_category.

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 gives clear mode-selection guidance: default compact text for reading/token efficiency, verbose=true for programmatic consumers, and group_by overriding verbose. It does not explicitly state when to choose this tool over related report tools, so it stops short of a 5.

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