lookup_record

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

With no annotations provided, the description carries the full burden. It explains that the tool returns the first match or all matches and uses an XLOOKUP analogy, but does not cover edge cases (e.g., no match), error handling, or performance characteristics. The behavior is partially disclosed but lacks completeness.

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 two sentences and very concise, with no unnecessary words. It is front-loaded with the core purpose. However, it could be slightly more structured by separating the what from the when-to-use.

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?

Given no output schema, the description explains what is returned (first match or all matches) but does not specify the format (e.g., returns record objects). It operates on a provided records array, which is implied but not explicitly stated. The sibling tools are mostly search tools, so the context of an in-memory lookup is fairly clear. Overall, it is mostly complete for a simple lookup tool.

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 100% coverage, so the parameters are already described. The description adds marginal value by clarifying 'returns the first match or all matches' which relates to the return_all parameter, but does not add meaning to field, value, records, or operator beyond the 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 clearly states the tool finds a record by field value, using analogies to VLOOKUP/XLOOKUP, and specifies it returns first or all matches. It distinguishes itself from sibling search tools by focusing on in-memory lookups on provided records rather than database searches.

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 explicitly says 'Use for finding a specific invoice, supplier, etc.', giving clear usage context. However, it does not mention when not to use it or provide alternatives like the sibling search tools for database-wide searches, though the context implies it's for in-memory lookups.

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