op_check_ref

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

With no annotations provided, the description fully carries the safety disclosure. It explicitly states that the field VALUE is never returned and lists the non-secret metadata returned (vault name, item title, field label, field type), which is essential for trust and safe use.

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, front-loaded with the action and safety guarantee, and contains no fluff. Every phrase adds value, making it both concise and effective.

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 single-parameter validation tool with no output schema, the description covers all necessary context: the input format, the validation purpose, the non-sensitive return data, and the usage scenario. It is fully self-sufficient even without annotations.

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 schema description already fully documents the parameter ('Secret reference to validate, in op://vault/item/field format.'), covering 100% of the parameter's meaning. The description adds no extra parameter semantics, so the baseline score of 3 is appropriate.

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 purpose with the verb 'validate' and the resource 'op://vault/item/field secret reference'. It also distinguishes itself from sibling tools like password_read and item_get by explicitly saying not to use those for the same purpose.

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?

It explicitly directs when to use the tool ('Use this to check a reference is correct before using it with op_run') and when not to ('do not use password_read/item_get with reveal just to check a reference exists'). This is excellent, unambiguous guidance.

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