x_list_member_set

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

Annotations already indicate this is a non-read-only, non-destructive, idempotent write. The description adds valuable context beyond annotations: the operation is reversible, the result reports the resulting is_member state, and it is disabled under a read-only policy. This gives the agent useful expectations without contradicting the 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 description is compact and front-loaded: it opens with the core action, then lists accepted parameter formats, then states behavioral results and policy constraints. Every sentence adds useful information with no filler.

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 simple 3-parameter shape, full schema coverage, annotations, and an output schema, the description provides the additional context an agent needs: own-list restriction, single-user-per-call behavior, reversibility, and result state. Nothing essential is missing for correct invocation.

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 coverage is 100%, with each parameter already described: user formats, action enum, and list_id formats. The description restates some of this information and adds the 'single user per call' constraint, but it does not materially expand beyond what the schema already provides.

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 verb and resource: add or remove a user from the authenticated user's list, with a single user per call. This distinguishes it from sibling tools like x_list_members or x_list_create. The 'add or remove' framing leaves no doubt about the tool's 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?

The description gives clear context for when to use the tool: modifying membership on the authenticated user's own list, one user at a time. It does not explicitly name alternative tools like x_list_members for viewing memberships, but the mutation-focused wording makes the intended use obvious and excludes read/list operations.

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