x_list_create

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

Beyond the annotations, the description discloses that lists are public by default, that name length and description length are constrained, that it returns the new list id, and that the tool is disabled under a read-only policy. This gives the agent concrete expectations about behavior and constraints.

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?

Two sentences pack in the purpose, parameter constraints, defaults, return value, and policy caveat. There is no filler, and the most important facts are front-loaded.

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 create operation, the description covers the operation, required inputs, optional inputs, defaults, return format, and policy restriction. No important information is missing for an agent to call it correctly.

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 already 100%, and the description adds meaningful semantics: which parameters are required vs optional, the public-by-default behavior of private, and the return value of the new list id. This goes well beyond a bare schema listing.

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 (create), the resource (an X/Twitter list), and the owner scope (authenticated user). This distinguishes it from siblings like x_list_update and x_list_delete without needing to inspect those tools.

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 makes the use case clear: creating a new list for the authenticated user, with required and optional fields. It does not name alternatives such as x_list_update for editing an existing list, so it lacks explicit exclusions, but the context is unambiguous.

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