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

Annotations already declare readOnlyHint=true, so the description does not need to re-state that it's a read operation. It adds value by explaining why the result matters (preferences and branding scoping), which helps the agent understand the tool's role. It does not contradict the annotations. The description could mention pagination behavior, but the added context is meaningful, so a 4 is appropriate.

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 with no fluff. The primary action is front-loaded, and the supporting rationale is concise and directly relevant. Every sentence 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?

Given the tool's simplicity—a read-only list operation with pagination—and the fact that the schema documents all parameters, the description is mostly complete. However, it does not mention the shape of the response (e.g., whether it returns tenant IDs or full objects) or default pagination behavior. Since there is no output schema, a brief note about return format would have made it fully complete, but the current level suffices for a capable agent.

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 provides detailed descriptions for all three parameters, including the opaque cursor token usage and the requirement to pass it back byte-for-byte. Since schema description coverage is 100%, the description adds no additional parameter semantics beyond the schema. Baseline 3 is correct.

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 function: 'List the tenants a user belongs to.' It also provides a specific verb and resource, and the added rationale about per-tenant preferences and branding distinguishes it from generic list tools like list_tenants or list_tenant_users. The purpose is unambiguous and distinct from siblings.

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 explains when to use the tool: to determine which tenant-scoped settings could apply to a user 'before you go looking for them.' This gives clear context on the intended use case, though it does not explicitly name alternatives or state when not to use it. Since it implies the correct selection among siblings, it earns a 4 rather than a 5.

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