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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuine context beyond that: the absence of any MCP-exposed mutation path and the fact that members are MANAGERs on the caller's own account. It does not describe the return shape or ordering, which is the only remaining gap.

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?

Three short sentences, each carrying distinct information: what it returns, what is not available, and which sibling to use instead. The alternative is placed last, after the reader knows what this tool is.

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 zero-parameter read tool with no output schema, the description covers identity, scope, safety, and alternatives well. The one omission is the returned record structure, which the description can only gesture at with 'and their roles' since no output schema exists to carry it.

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 tool takes zero parameters, so the baseline is 4. The description correctly says nothing about inputs, and the `userId` mention is clearly attributed to other tools rather than implying a parameter here.

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?

States the resource and its content precisely: people with access to this account and their roles. It also explicitly distinguishes itself from the sibling `subaccount_list` and clarifies that team members are people, not accounts, which removes the main ambiguity an agent would have.

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?

Gives an explicit routing rule: for agency sub-accounts read with a `userId` argument, use `subaccount_list` instead. It also closes off dead ends by stating that inviting, removing, and role changes are not exposed over MCP, so the agent will not search for nonexistent write tools.

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