Vector Similarity Search

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

Beyond the readOnly and idempotent annotations, the description discloses the most important runtime behavior: this is a placeholder and will return a not-implemented message. This is critical information that the annotations alone could not convey. There is no contradiction between the description and 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 core message is concise and the placeholder warning is front-loaded, which is helpful. However, the Args and Returns sections largely duplicate the input schema without adding new information, so not every sentence truly earns its place.

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?

Between the schema, annotations, and description, a caller knows the parameters, safety profile, intended behavior, and the fact that the tool is currently non-functional. The main gaps are the lack of sibling-tool alternatives and the absence of a more concrete return format, but these are minor for a placeholder 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 already describes all four parameters with types, defaults, ranges, and required status, so schema coverage is 100%. The description's Args section merely repeats that information and adds no additional semantic nuance. A baseline of 3 is appropriate when the schema carries the parameter documentation 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 opens with a specific verb and resource: 'Search knowledge entries by vector similarity in TiDB', which clearly conveys the intended function. The placeholder note adds important context without obscuring the purpose. However, it does not explicitly differentiate this tool from the sibling tidb_search_knowledge tool.

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 placeholder warning gives an explicit reason not to call this tool now: 'Currently returns a not-implemented message.' That provides some usage guidance. But it never states when to use this tool versus the sibling list/get/search tools, nor does it recommend an alternative.

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