cross_workbook_lookup

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

The readOnlyHint annotation covers the non-destructive nature, and the description does not contradict it. However, the description adds no extra behavioral context beyond the core concept—no mention of how matches are handled, return format, or impact of parameters like join_type or match_mode. Minimal value beyond 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 a single sentence with no redundant wording—highly concise and front-loaded. However, for a tool with 24 parameters, this brevity borders on under-specification, though it still earns a 4 for efficiency.

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?

Despite having 24 parameters, no output schema, and only a terse one-line description, the tool definition lacks any explanation of expected outputs, parameter interactions, or practical usage context. The description is far from complete for a tool of this complexity.

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 input schema has 0% description coverage across 24 parameters, and the tool description does not compensate. It only references 'source' and 'lookup' generically, failing to explain critical parameters such as join_type, match_mode, schema_mode, or lookup_select. The agent is left without sufficient meaning to set parameters correctly.

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 the tool's action ('Enrich one workbook dataset from matching rows') and specifies the resource involved ('one or more lookup workbooks'). This distinguishes it from simple read tools, though it does not explicitly name alternative tools.

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 phrase 'Enrich one workbook dataset from matching rows' implies the use case for cross-workbook lookups, but there is no explicit when-to-use guidance or mention of alternatives like query_table or union_tables. Usage context is only inferred, not stated.

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