ChatGPT Chat Completion With Tool Calling

arazzo: 1.0.1
info:
  title: ChatGPT Chat Completion With Tool Calling
  summary: Run a chat completion offering a function tool and resolve the tool call.
  description: >-
    Sends a user message to the Chat Completions API along with a single
    function tool definition. The flow branches on the choice finish_reason:
    when the model decides to call the tool it issues a second completion that
    feeds the simulated tool result back as a tool message to obtain the final
    answer, and when the model answers directly it returns that answer. Every
    step spells out its request inline so the flow can be read and executed
    without opening the underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: chatCompletionsApi
  url: ../openapi/chatgpt-chat-completions-api-openapi.yml
  type: openapi
workflows:
- workflowId: chat-completion-tool-call
  summary: Offer a function tool to a chat completion and resolve the tool call loop.
  description: >-
    Creates a chat completion with a function tool, branches on finish_reason,
    and when a tool call is returned sends a follow-up completion that supplies
    the tool result so the model can produce its final response.
  inputs:
    type: object
    required:
    - apiKey
    - model
    - userMessage
    - toolName
    - toolResult
    properties:
      apiKey:
        type: string
        description: OpenAI API key used as the Bearer credential.
      model:
        type: string
        description: Model ID used for the completion (e.g. gpt-4o).
      userMessage:
        type: string
        description: The user message that may trigger a tool call.
      toolName:
        type: string
        description: The name of the function tool offered to the model.
      toolResult:
        type: string
        description: The simulated tool output fed back to the model.
  steps:
  - stepId: createCompletion
    description: >-
      Create a chat completion that offers a single function tool and lets the
      model decide whether to call it.
    operationId: createChatCompletion
    parameters:
    - name: Authorization
      in: header
      value: "Bearer $inputs.apiKey"
    requestBody:
      contentType: application/json
      payload:
        model: $inputs.model
        messages:
        - role: user
          content: $inputs.userMessage
        tools:
        - type: function
          function:
            name: $inputs.toolName
            description: A tool the model may call to satisfy the request.
            parameters:
              type: object
              properties:
                query:
                  type: string
              required:
              - query
        tool_choice: auto
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      completionId: $response.body#/id
      finishReason: $response.body#/choices/0/finish_reason
      toolCallId: $response.body#/choices/0/message/tool_calls/0/id
      toolCallArgs: $response.body#/choices/0/message/tool_calls/0/function/arguments
      directContent: $response.body#/choices/0/message/content
    onSuccess:
    - name: modelCalledTool
      type: goto
      stepId: resolveToolCall
      criteria:
      - context: $response.body
        condition: $.choices[0].finish_reason == "tool_calls"
        type: jsonpath
    - name: modelAnsweredDirectly
      type: end
      criteria:
      - context: $response.body
        condition: $.choices[0].finish_reason == "stop"
        type: jsonpath
  - stepId: resolveToolCall
    description: >-
      Send a follow-up completion that replays the assistant tool call and
      supplies the tool result as a tool-role message so the model can answer.
    operationId: createChatCompletion
    parameters:
    - name: Authorization
      in: header
      value: "Bearer $inputs.apiKey"
    requestBody:
      contentType: application/json
      payload:
        model: $inputs.model
        messages:
        - role: user
          content: $inputs.userMessage
        - role: assistant
          content: $steps.createCompletion.outputs.directContent
        - role: tool
          content: $inputs.toolResult
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      finalContent: $response.body#/choices/0/message/content
      finalFinishReason: $response.body#/choices/0/finish_reason
      totalTokens: $response.body#/usage/total_tokens
  outputs:
    completionId: $steps.createCompletion.outputs.completionId
    firstFinishReason: $steps.createCompletion.outputs.finishReason
    finalContent: $steps.resolveToolCall.outputs.finalContent
    totalTokens: $steps.resolveToolCall.outputs.totalTokens