listKnownDomains

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds behavioral value by disclosing that the result contains existing vocabulary and query counts, which is useful beyond the annotation-only picture.

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?

One sentence carries the purpose, the resource, and the intended reuse without any filler. Every word contributes, and the key discriminator ('for reuse in listQueries filters') appears at the end for natural reading.

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 simple read-only tool with one documented parameter, an output schema, and safety annotations, the description is complete enough. An agent can infer what it returns, why to call it, and that it is non-destructive without needing additional context.

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?

Schema description coverage is 100% for the single required parameter, and the schema already documents that 'connection' is a database name and instructs agents to call listConnections rather than guess. The tool description itself adds no parameter-level detail, so the baseline 3 applies.

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 states a specific verb ('Discover') and a precise resource: 'existing business-domain vocabulary and query counts.' It also names the downstream use ('reuse in listQueries filters'), which clearly distinguishes it from plain enumeration tools like listKnownKinds or listKnownTags.

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 gives clear context by saying the output is meant for reuse in listQueries filters, so an agent knows when it is relevant. It does not explicitly say when not to use alternatives like listKnownKinds or listKnownTags, but the intended use case is specific enough to route selection.

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