Lookup Table

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is known. The description adds that it queries sys_db_object, returns specific fields (name, label, parent, extendable, number prefix, scope), and that search is case-insensitive partial matching. This enriches the tool's behavior beyond the annotations, though it doesn't discuss pagination limits (covered by schema) or rate limits.

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 a summary line, a bulleted use-case list, and a returns line. It avoids redundancy and uses short, scannable phrases. Every section adds value, making it both concise and informative.

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 metadata lookup tool, the description covers purpose, use cases, and return fields. The schema documents all parameters, and annotations declare safety. No output schema exists, so explaining the return fields is valuable and done well. The description is sufficiently complete for an agent to select and invoke the tool correctly.

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 provides comprehensive descriptions for all three parameters, achieving 100% coverage. The description's mention of partial matching and examples aligns with the schema's search_term description but adds no new semantic information. Baseline of 3 is appropriate since schema carries the full burden.

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 searches ServiceNow tables by name or label, queries the sys_db_object table, and provides concrete use cases. It distinguishes itself from sibling lookup tools by specifying the target resource (tables) and the underlying system table. This is a specific verb+resource definition with clear scope.

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 'Use this tool to' section provides four explicit scenarios, including verifying table existence before query_table, discovering internal names, finding related tables, and checking hierarchy. While it doesn't explicitly name alternative tools, the scenarios imply when this tool is appropriate. This is clear contextual guidance, though slightly lacking in explicit exclusions.

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