Claude Tool Use Round Trip

arazzo: 1.0.1
info:
  title: Claude Tool Use Round Trip
  summary: Offer the model a tool, capture its tool_use request, then return a tool_result for a final answer.
  description: >-
    A complete tool-use round trip. The workflow sends a prompt along with a
    tool definition and a tool_choice that forces the model to call the tool.
    The model responds with a tool_use block requesting the tool. The workflow
    then sends a second request that replays the conversation and supplies a
    tool_result block containing the tool's output, letting the model produce a
    final natural-language answer grounded in that result. Every step spells out
    its request inline — including the required x-api-key and anthropic-version
    headers — so the flow can be read and executed without opening the
    underlying OpenAPI description.
  version: 1.0.0
sourceDescriptions:
- name: claudeApi
  url: ../openapi/claude-messages-api.yml
  type: openapi
workflows:
- workflowId: tool-use-round-trip
  summary: Drive a single tool-use cycle from tool_use request to grounded final answer.
  description: >-
    Sends a prompt with a tool definition, captures the model's tool_use id and
    name, then returns a tool_result so the model can answer using the tool
    output.
  inputs:
    type: object
    required:
    - apiKey
    - model
    - prompt
    - toolName
    - toolDescription
    - toolInputSchema
    - toolResult
    properties:
      apiKey:
        type: string
        description: Anthropic API key sent in the x-api-key header.
      anthropicVersion:
        type: string
        description: Value for the required anthropic-version header.
        default: '2023-06-01'
      model:
        type: string
        description: The model to use for both turns.
      prompt:
        type: string
        description: The user prompt that should trigger the tool call.
      toolName:
        type: string
        description: The name of the tool offered to the model.
      toolDescription:
        type: string
        description: A description of what the tool does and when to use it.
      toolInputSchema:
        type: object
        description: JSON Schema object describing the tool's input parameters.
      toolResult:
        type: string
        description: The output of the tool, returned to the model as a tool_result.
      maxTokens:
        type: integer
        description: Maximum number of tokens to generate per turn.
        default: 1024
  steps:
  - stepId: requestToolUse
    description: >-
      Send the prompt with a tool definition and force tool use, capturing the
      tool_use block id and name from the model's response.
    operationId: createMessage
    parameters:
    - name: x-api-key
      in: header
      value: $inputs.apiKey
    - name: anthropic-version
      in: header
      value: $inputs.anthropicVersion
    requestBody:
      contentType: application/json
      payload:
        model: $inputs.model
        max_tokens: $inputs.maxTokens
        messages:
        - role: user
          content: $inputs.prompt
        tools:
        - name: $inputs.toolName
          description: $inputs.toolDescription
          input_schema: $inputs.toolInputSchema
        tool_choice:
          type: tool
          name: $inputs.toolName
    successCriteria:
    - condition: $statusCode == 200
    - condition: $response.body#/stop_reason == "tool_use"
    outputs:
      assistantContent: $response.body#/content
      toolUseId: $response.body#/content/0/id
      toolUseName: $response.body#/content/0/name
  - stepId: returnToolResult
    description: >-
      Replay the conversation and supply the tool output as a tool_result block
      keyed to the captured tool_use id so the model can produce a final answer.
    operationId: createMessage
    parameters:
    - name: x-api-key
      in: header
      value: $inputs.apiKey
    - name: anthropic-version
      in: header
      value: $inputs.anthropicVersion
    requestBody:
      contentType: application/json
      payload:
        model: $inputs.model
        max_tokens: $inputs.maxTokens
        messages:
        - role: user
          content: $inputs.prompt
        - role: assistant
          content: $steps.requestToolUse.outputs.assistantContent
        - role: user
          content:
          - type: tool_result
            tool_use_id: $steps.requestToolUse.outputs.toolUseId
            content: $inputs.toolResult
        tools:
        - name: $inputs.toolName
          description: $inputs.toolDescription
          input_schema: $inputs.toolInputSchema
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      messageId: $response.body#/id
      content: $response.body#/content
      stopReason: $response.body#/stop_reason
      usage: $response.body#/usage
  outputs:
    toolUseId: $steps.requestToolUse.outputs.toolUseId
    toolUseName: $steps.requestToolUse.outputs.toolUseName
    messageId: $steps.returnToolResult.outputs.messageId
    content: $steps.returnToolResult.outputs.content
    usage: $steps.returnToolResult.outputs.usage