kalshi_create_subaccount

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

Annotations indicate a non-read-only, non-destructive operation; the description aligns with that and adds useful behavioral details: subaccounts are numbered sequentially from 1, the limit of 63 numbered accounts, and the HTTP method POST. This goes beyond the annotations to explain what happens during creation.

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 includes essential facts in a few sentences. However, it begins with a redundant 'Create Subaccount' heading that repeats the action from the following sentence, which slightly detracts from structure. Overall, it is efficient.

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 nature (one optional parameter, no output schema), the description adequately covers purpose, prerequisites, limits, and HTTP endpoint. It does not describe the response format, but that is a minor omission for a creation tool where the created resource's identity can be inferred from the numbering rules.

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 describes exchange_index with 100% coverage, including default behavior. The description does not mention this parameter, adding no semantic value beyond the schema. Since schema coverage is high, baseline 3 is appropriate.

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?

Description clearly states the action: 'Creates a new subaccount for the authenticated user.' The verb 'Create' and resource 'subaccount' are specific and distinguish it from sibling tools that update, transfer, or query subaccounts. The description leaves no ambiguity about the tool's function.

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?

Provides usage context by noting the Advanced API tier requirement and the maximum number of subaccounts (63 + primary). It does not explicitly name alternatives, but the creation action is self-evidently distinct from sibling tools. This is clear context without explicit exclusions.

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