Hugging Face Grounded Text Generation

arazzo: 1.0.1
info:
  title: Hugging Face Grounded Text Generation
  summary: Find a text-generation model on the Hub, confirm it, then run hosted text generation.
  description: >-
    Combines the Hub API with the hosted Inference API. The workflow searches the
    Hub for text-generation models, confirms the top match exists, and then runs
    a text-generation inference call against that model with tuning parameters.
    The flow handles the model-loading (503) case by documenting it as a known
    response. 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: hubApi
  url: ../openapi/hugging-face-hub-api.yml
  type: openapi
- name: inferenceApi
  url: ../openapi/hugging-face-inference-api.yml
  type: openapi
workflows:
- workflowId: grounded-text-generation
  summary: Discover a text-generation model on the Hub and generate text with it.
  description: >-
    Searches the Hub for a text-generation model, verifies it, and runs a hosted
    text-generation inference request against the selected model.
  inputs:
    type: object
    required:
    - hfToken
    - search
    - prompt
    properties:
      hfToken:
        type: string
        description: Hugging Face access token used as a Bearer credential.
      search:
        type: string
        description: Full-text search query for finding a model on the Hub.
      prompt:
        type: string
        description: The input text prompt to generate from.
      maxNewTokens:
        type: integer
        description: Maximum number of new tokens to generate.
        default: 128
      temperature:
        type: number
        description: Sampling temperature.
        default: 0.7
  steps:
  - stepId: findModel
    description: >-
      Search the Hub for text-generation models matching the query, sorted by
      downloads, and take the most popular match.
    operationId: $sourceDescriptions.hubApi.listModels
    parameters:
    - name: search
      in: query
      value: $inputs.search
    - name: pipeline_tag
      in: query
      value: text-generation
    - name: sort
      in: query
      value: downloads
    - name: limit
      in: query
      value: 5
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      modelId: $response.body#/0/id
    onSuccess:
    - name: haveModel
      type: goto
      stepId: confirmModel
      criteria:
      - context: $response.body
        condition: $.length > 0
        type: jsonpath
  - stepId: confirmModel
    description: >-
      Confirm the selected model exists and read its tags before issuing a paid
      inference request.
    operationId: $sourceDescriptions.hubApi.getModel
    parameters:
    - name: repo_id
      in: path
      value: $steps.findModel.outputs.modelId
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      confirmedModelId: $response.body#/id
  - stepId: generateText
    description: >-
      Run a hosted text-generation inference request against the confirmed model.
      A 200 returns the generated text; a 503 indicates the model is still
      loading and the request may be retried.
    operationId: $sourceDescriptions.inferenceApi.textGeneration
    parameters:
    - name: Authorization
      in: header
      value: Bearer $inputs.hfToken
    - name: model_id
      in: path
      value: $steps.findModel.outputs.modelId
    requestBody:
      contentType: application/json
      payload:
        inputs: $inputs.prompt
        parameters:
          max_new_tokens: $inputs.maxNewTokens
          temperature: $inputs.temperature
          return_full_text: false
        options:
          use_cache: true
          wait_for_model: true
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      generatedText: $response.body#/0/generated_text
  outputs:
    modelId: $steps.confirmModel.outputs.confirmedModelId
    generatedText: $steps.generateText.outputs.generatedText