Create a new user in the pet store API. Use this tool to add a user record.
Create user.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| result | No | Response from the tool |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description 'Create user.' adds no behavioral details beyond the annotations, which already flag destructiveHint=true and readOnlyHint=false. It provides no context about side effects, auth requirements, response behavior, or any constraints. It does not contradict the annotations, but it offers no additional transparency.
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 extremely short, but this is under-specification rather than efficient conciseness. The two-word phrase carries no information beyond what the tool name already expresses, so the single sentence does not earn 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?
Even with no parameters and an output schema, the description is insufficiently complete. An agent receives no context about whether this is the singular creation endpoint, how it relates to createUsersWithListInput, what the operation destroys or overwrites, or what a successful result looks like.
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?
There are zero parameters, so the schema already covers all input semantics with 100% coverage. The description has nothing to add, and no compensation is required.
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 is a word-for-word restatement of the tool name: 'createUser' becomes 'Create user.' It names a verb and resource but adds no detail that the name doesn't already contain. It also does not explicitly distinguish this singular operation from sibling createUsersWithListInput.
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?
No usage guidance is provided. The description does not say when to prefer createUser over createUsersWithListInput, nor does it mention that updateUser or deleteUser operate on existing users.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.