This skill provides procedural knowledge for fine-tuning Large Language Models (both Open Models and Gemini Models) using Agent Platform's tuning service. It covers the entire lifecycle from environment setup and data preparation to job configuration, monitoring, and deployment.

Workflow Decision Tree

1. Model Category Identification: Has the user explicitly stated whether they want to tune an Open Model or a Gemini Model?

   • No → STOP. Ask the user if they want to tune an Open Model or a Gemini Model. CRITICAL EXCEPTION for Environment Setup Requests: If the user is specifically asking for environment setup instructions (e.g. "What environment setup is needed?"), you MUST provide the full Phase 0 environment setup instructions in your initial response, simultaneously with asking clarifying questions about the model category.
   • If the user provides a specific tuning purpose, you should recommend three models: one Open Model, one Gemini Model, and a third generally recommended choice. Briefly list the pros and cons of each (e.g., Gemini models might be more expensive, etc.). CRITICAL: You must read references/models.md during this step and only recommend models explicitly listed in that catalog. Do not recommend unsupported models like Mistral. If the user names a model that is not in the catalog, follow the fallback rule in that catalog. Do not proceed with model configuration until the category is confirmed.
   • Yes → Proceed.

2. Environment Check: Has the environment (Auth, APIs, IAM, Venv) been initialized?

   • No → Go to Phase 0: Environment & IAM Setup.
   • Yes → Proceed.

3. Dataset Status: Is the dataset ready in JSONL format, is its structure valid for tuning, and is it uploaded to Google Cloud Storage?

   -   **No** → Go to [Phase 1: Dataset Preparation & Upload](#phase-1).
   -   **Yes** → Proceed.
   

4. Column Selection Confirmation: Have you presented the columns to the user and confirmed the mapping?

   • No → STOP. You must show samples and get user confirmation on column mapping as described in Phase 1.0 before proceeding.
   • Yes → Proceed.

5. Configuration: Has the user provided the target model and hyperparameters, or explicitly agreed to your recommendations?

   • No → Go to Phase 2: Model Configuration & Recommendation.
   • Yes → Proceed.

6. Job Status: Has the tuning job been submitted?

   -   **No** → Go to
       [Phase 3: Tuning Job Execution](#phase-3-tuning-job-execution).
   -   **Yes** → Proceed.
   

7. Job Completion: Is the tuning job complete?

   -   **No** → Go to [Phase 4: Monitoring](#phase-4-monitoring).
   -   **Yes** → Proceed.
   

8. Deployment: Has the tuned model been deployed (if required)?

   -   **No** → Go to [Phase 5: Model Deployment](#phase-5-model-deployment).
   -   **Yes** → Task Complete.
   

Phase 0: Environment & IAM Setup {#phase-0}

Ensure the foundational environment is ready before proceeding.

0.1 Authentication & Project Context

• Check if gcloud CLI is installed. If it is not installed, prompt the user for permission to install it before proceeding. If it is installed, update it:

gcloud components update --quiet > /dev/null 2>&1

• Verify gcloud auth list. If not authenticated, run gcloud auth login.
• Ensure project is known. Use gcloud config get project to retrieve the current project.
• CRITICAL: Ask for Confirmation. You must prompt the user to confirm the retrieved project before proceeding, in case they want to switch to a different one. The location must also be confirmed — see section 0.2 for which location to propose, which depends on the model category.

0.2 Location

Location handling depends on the model category you established in the workflow decision tree. The two categories have different supported locations — never apply one category's locations to the other.

• Open models share one fixed location set, and global is the recommended choice.
• Gemini models differ per model and must be looked up. global is not accepted for them today.

If the user names a location that is not valid for their model and category, STOP. Respond with an error naming the requested location as unsupported, list the locations that are valid, and do NOT ask for a dataset, do NOT proceed with any other setup step, and do NOT silently retry elsewhere.

Open Models (RECOMMEND: global)

Recommend global and confirm it with the user. Propose it as a single recommended choice rather than making the user pick a region first, and do not steer them toward a specific region instead.

These are the only locations available for open model tuning:

• global (the recommended choice)
• us-central1
• europe-west4
• us-west1
• us-east5
• asia-southeast1

The global endpoint automatically selects a supported region that has available capacity, so it is the most likely to be scheduled successfully. Pinning a region up front restricts the job to that one region's capacity, which is why global is the recommended location for open model tuning.

• The user named a location → use it verbatim, provided it is global or one of the regions listed above. Do not talk them out of it.
• The user asked which locations are supported → answer the question. Share the list above and say that global is recommended and why. Never withhold it.
• The user did not name a location → propose global and ask them to confirm it before you proceed. Say that global lets the service pick a region with available capacity. Do NOT silently assume global.

The point of proposing a single choice is to avoid making region selection a decision the user must resolve before anything else can happen — that ordering is what previously blocked people. It is not a reason to hide the list: quote it whenever the user asks, and quote it when rejecting an unsupported location.

Fall back to an explicit region only in the cases below, and tell the user why you are doing so:

• CMEK. Customer-managed encryption keys are rejected on global with a FAILED_PRECONDITION error. A CMEK-protected job must name the region that holds the key.

• Data residency. If the user requires the job to stay in a specific jurisdiction, honor their region. global currently runs the job in either us-central1 or europe-west4.

If a global job is accepted but then fails with a FAILED_PRECONDITION error saying the model does not support global endpoint tuning, that model is not onboarded to the global endpoint yet. The model itself is still tunable: resubmit once in an explicit region from the list above (us-central1 is the safest choice) and tell the user why you switched.

Working with a global job

• The API host stays aiplatform.googleapis.com. There is no global-aiplatform.googleapis.com host.
• The service resolves global to a real region at run time. Sub-resources (the tuned model, checkpoints, TensorBoard) come back with that real region in their resource names, not global. Read the location out of the returned resource name before using it for monitoring or deployment; never assume it is still global.
• Quota is shared across regions, so pinning a region does not grant extra quota.

Gemini Models (per-model, look it up)

global is not accepted for Gemini tuning today — the service rejects it at job creation with a FAILED_PRECONDITION error, so do not propose it here.

There is no single region allowlist for Gemini. Supported tuning regions vary by model and by model version: some Gemini models are restricted to two regions while others support many more. Do NOT reuse the open model list above, and do NOT assume a region carries over from another Gemini model.

Before submitting, look up the chosen model in the supervised fine-tuning documentation and read its "Supported endpoint for model tuning" row: supervised tuning

• The user asked which regions are supported → look up that specific model and tell them what the docs say. Do not answer from memory or from the open model list, and do not answer for a different Gemini model.
• The model's row names specific regions → the user's region must be one of them. If it is not, STOP and report the supported regions for that model.
• The model's row is absent or the docs are unclear → ask the user for the region rather than guessing one.

Confirm the region with the user before proceeding. Note that some Gemini models also restrict CMEK and serve tuned models only on the us and eu multi-region endpoints, so check the same table for those limits before promising them.

0.3 Enable APIs

Ensure aiplatform.googleapis.com and storage.googleapis.com are enabled.

gcloud services enable aiplatform.googleapis.com storage.googleapis.com \
    --project=YOUR_PROJECT

0.4 IAM Permissions

Verify the following identities have the required roles.

• Agent Platform Service Agent: [email protected]
• Managed OSS Fine Tuning Service Agent: service-PROJECT_NUMBER@gcp-sa-vertex-moss-ft.iam.gserviceaccount.com
• User Identity: The account running the commands.

0.5 Python Dependencies

The scripts in this skill import vertexai (from google-cloud-aiplatform), google-genai, google-cloud-storage, and datasets.

CRITICAL AGENT INSTRUCTION: Do not create a virtual environment, and do not install anything before checking. A venv starts empty and hides packages the environment already provides, forcing a redundant several-minute install.

Probe first and install only if the probe fails:

python3 -c "import vertexai, google.genai, google.cloud.storage, datasets" \
  || pip install -r references/requirements.txt

Then run every script with a plain python3 scripts/... — no activation prefix.

The references/requirements.txt pins are a fallback for an environment that does not already provide these SDKs. Do not apply them on top of a working environment: they would downgrade packages other tools may share.

Phase 1: Dataset Preparation & Upload {#phase-1}

1.0 Dataset Discovery & Confirmation

• User-Provided Dataset Verification: If the user specifies a dataset filename or path in their prompt, verify its existence in the workspace (e.g. via script execution or checking for typos).
  • If the file cannot be found anywhere, you MUST inform the user that the dataset file does not exist or cannot be accessed. You MUST prompt the user to provide a valid dataset path. Alternatively, if candidate dataset files are found in the workspace during your search, you MUST present the candidates to the user and ask them to select one. You MUST stop tool execution immediately after reporting the missing file or presenting candidates, and wait for the user's response. Do NOT ask for 90/10 validation split permission, and do NOT attempt to upload the dataset before receiving a valid dataset file selection from the user.
  • If the file is found and verified, proceed to Step 1.1 Formatting & Validation below.
• Auto-Discovery: From User Bucket: If the user does not have a dataset and no suitable alternative is found in the Hugging Face reference, offer to search the user's GCS buckets for potential training data. Prioritize searching for files with extensions like .jsonl, .json, .csv, and .parquet. If such files are found, read the first few lines/records of each to determine if they contain text-based data suitable for tuning (e.g., prompt/completion pairs) that can be modified to follow Data Preparation Guide and is related to the tuning task requested. DO NOT search without prompting first.
• Auto-Discovery: From Task to Huggingface: If the user has a specific task, refer to Huggingface Datasets Reference and recommend a dataset from this if one exists. For each dataset recommended, provide some information about the dataset and provide some reasonable splits. > [!IMPORTANT] > CRITICAL: Ask for Confirmation and Column Selection. Do not proceed > with dataset preparation or upload until you perform the following > steps and get user confirmation: > 1. Dataset and Split Confirmation: Present the dataset and > available splits to the user and have them confirm which to use. > 2. Column Selection (Hugging Face or Custom Datasets): You must: > - Provide a list of all available columns in the selected dataset > split. > - Show a few samples from the dataset to help the user > understand the content and make the choice of columns. > - Recommend which columns should be mapped to prompt (or user > message) and completion (or assistant response), offering a few > reasonable options if applicable. > - Ask the user to confirm the column mapping or specify which > columns to use.

1.1 Formatting & Validation

• Conversion: If data is in CSV, JSON, or Parquet, use scripts/prepare_dataset.py to convert.
• Validation Split Confirmation: If the user only provides a training dataset, you must prompt the user to seek permission to split the training dataset 90/10 to form a validation dataset (using --validation_split 0.1). If they agree, proceed with the split. If they decline, just use the training dataset without a validation dataset. Do NOT offer an 80/20 split; the tuning service rejects it, for the reason given in Data Preparation Guide.
• Validation: If data is already in JSONL, validate it before uploading. Simply having a .jsonl extension is not enough. You must verify that the content schema is valid for tuning (e.g. correct system/user/model roles).

python3 scripts/prepare_dataset.py \
    --input my_data.jsonl \
    --format <messages|messages_gemini> \
    --validate_only

(Use --format messages for open models and --format messages_gemini for Gemini models.) - Refer to Data Preparation Guide for required schemas.

1.2 Upload

Upload formatted .jsonl files to GCS using a unique directory (e.g., with a datetime timestamp) to avoid overwriting outputs from different runs.

ARTIFACTS="gs://YOUR_BUCKET/tuning_agent_job_<datetime>/dataset.jsonl"
gcloud storage cp dataset.jsonl "$ARTIFACTS"

Phase 2: Model Configuration & Recommendation {#phase-2}

Help the user choose the best model and parameters. Always seek user confirmation before submitting the job.

• If the user does not specify a specific model in their prompt, calculate recommendations based on the Models Catalog.
• Prompt for Confirmation: Present the recommended model to the user and ask for their confirmation before configuring hyperparameters.

2.1 Configuration

For Open Models

• Recommend tuning_mode, epochs, learning_rate, and adapter_size based on the Tuning Guide and model-specific baselines in the Models Catalog.

Verify the Live Model ID

Before submitting the job, run scripts/list_models.py and pick --base_model only from its models output. Do not invent IDs or version numbers.

python3 scripts/list_models.py --project YOUR_PROJECT --filter gemini

Output: {"models": [...], "total_count": N, "truncated": bool}.

• For Gemini, strip google/ and @default (e.g. google/gemini-2.5-flash@default → gemini-2.5-flash); for open models, pass publisher/family@version as-is.
• Skip Gemini variants ending in -embedding, -tts, -image, -computer-use, or -native-audio; they are not tunable.
• If truncated is true, re-run with a tighter --filter (e.g. gemini-2.5) before deciding the target version is unavailable.
• If models is empty, stop and ask the user.

2.2 Calculating Cost (Open Models Only)

• We can calculate a rough estimate of cost of tuning based on the dataset and the selected model in the Models Catalog:

  python3 scripts/calculate_cost.py \
      --input my_data.jsonl \
      --model MODEL_NAME \
      --tuning_mode TUNING_MODE \
      --epochs epochs
  

  --model takes either the display name (Qwen 3 8B) or the same resource name you pass to --base_model (qwen/qwen3@qwen3-8b), so the value chosen in Step 2.1 can be reused as-is.

[!NOTE] Handling Missing Dataset Errors: If scripts/calculate_cost.py fails because the dataset file (e.g. my_data.jsonl or dummy_data.jsonl) cannot be found, you MUST inform the user that the dataset file does not exist or cannot be accessed. You MUST prompt the user to provide a valid dataset path, and stop tool execution immediately to wait for their response. Do NOT retry or loop, do NOT invent a specific cost number, and do NOT prompt for job submission approval before receiving a valid dataset from the user.

• Prompt for Confirmation: Present the recommended hyperparameter configuration and estimated cost to the user and ask for their approval before proceeding to job submission. Make sure to note that the estimated cost is just an estimate and can vary from actual billing costs.

Phase 3: Tuning Job Execution {#phase-3-tuning-job-execution}

CRITICAL Pre-Flight Check (GCS Verification): Before you propose a confirmation prompt or submit any tuning job, you MUST verify that the specified training dataset GCS URI (e.g. gs://dummy_bucket/dataset.jsonl or gs://YOUR_BUCKET/...) actually exists and is accessible. Run gcloud storage ls $DATASET_URI (or gsutil ls).

• If the verification fails (e.g. BucketNotFound, 404, AccessDenied, or indicating a dummy/missing bucket), you MUST inform the user that the GCS bucket or dataset does not exist or cannot be accessed. You MUST prompt the user to provide a valid GCS URI for the dataset, and stop tool execution immediately to wait for their response. Do NOT propose a confirmation prompt and do NOT execute any tuning scripts before receiving a valid dataset URI from the user.
• If the verification succeeds, proceed to propose the confirmation prompt below.

For Gemini Models

Check if scripts/tune_gemini_model.py exists.

• If scripts/tune_gemini_model.py exists: Submit the Gemini model tuning job using this script.

  python3 scripts/tune_gemini_model.py
  

• If scripts/tune_gemini_model.py does not exist: Instruct the user to manually configure and submit the tuning job via the Google Cloud Console UI or using the Agent Platform SDK for Python.

For Open Models

Submit the open model tuning job using scripts/tune_open_model.py. Identify the model id using available models documentation at documentation.

--base_model takes a publisher model resource name ({publisher}/{model_id}@{version_id}), not the display name shown in the catalog. See "Model Resource Name Format" in references/models.md for the format, verified examples, and how to look up a name you do not have.

python3 scripts/tune_open_model.py \
    --project YOUR_PROJECT \
    --location global \
    --base_model BASE_MODEL_ID \
    --train_dataset gs://YOUR_BUCKET/tuning_agent_job_<datetime>/dataset.jsonl \
    --output_uri gs://YOUR_BUCKET/tuning_agent_job_<datetime>/output \
    --epochs EPOCHS \
    --learning_rate LR \
    --tuning_mode MODE

This script is open model only, and --location falls back to global if omitted. Always pass the location the user confirmed in section 0.2 explicitly, so it is visible in the command string you present for approval.

[!WARNING] --output_uri is required for open models. The Python SDK declares it as output_uri: Optional[str] = None, but the tuning backend rejects open model jobs that omit it with INVALID_ARGUMENT: The output_uri field is required for this model. Treat the SDK's "optional" signature as wrong here and always pass a GCS destination.

Because the flag is mandatory, you must establish where the tuned model is written before you can submit. Never invent a bucket name, derive one from the project number, or run gcloud storage buckets create unprompted. Creating a bucket is a mutating action and is subject to the Tier M confirmation policy below.

• The user named a bucket or URI → use it, appending a unique per-job directory as in section 1.2.
• A bucket was already used for the dataset upload in section 1.2 → propose reusing it for the output and ask the user to confirm.
• Neither → STOP and ask the user where they want the tuned model stored. Offer to create a bucket for them as one of the options. If they accept, propose the exact bucket name and location, get explicit confirmation, and only then create it.

[!IMPORTANT] Interactive Confirmation Required (Tier M): Before proceeding with job submission, you MUST present the proposed command string showing all literal flags in a confirmation prompt to the user with 'Yes' and 'No' options.

CRITICAL: When presenting this confirmation prompt to the user, you MUST output it as a direct plain text response and stop tool execution immediately. Do NOT call any command execution or interactive tools in the same turn, as unexpected tool calls may be auto-replied by the simulation harness and cause an infinite loop. Yield immediately for the user's reply.

Phase 4: Monitoring {#phase-4-monitoring}

Monitor the job via the Cloud Console link provided in the script output. --location is required and must be the same location you submitted with: an open model job submitted on global is polled with --location global, even though the work runs in a real region behind the scenes.

Additionally, ask the user if they want you to monitor the job status for them in the background. If they agree, execute scripts/monitor_tuning_job.py as a background task to periodically poll the job status and notify the user to show the status. If the user declines, leave it completely to the user to check on the status.

Phase 5: Model Deployment {#phase-5-model-deployment}

Once the tuning job is SUCCEEDED, deploy the model.

Deployment requires a real region — --region=global is not valid here. If the job ran on global, read the region out of the tuned model's resource name (projects/.../locations/<REGION>/models/...) and deploy there; do not guess.

ARTIFACTS="gs://YOUR_BUCKET/tuning_agent_job_<datetime>/output/postprocess/node-0/checkpoints/final"
gcloud ai model-garden models deploy \
    --project=YOUR_PROJECT \
    --region=YOUR_LOCATION \
    --model="$ARTIFACTS" \
    --machine-type=MACHINE_TYPE \
    --accelerator-type=ACCELERATOR_TYPE \
    --accelerator-count=COUNT

[!IMPORTANT] Interactive Confirmation Required (Tier M): Before proceeding with deployment, you MUST present the proposed command string showing all literal flags in a confirmation prompt to the user with 'Yes' and 'No' options.

CRITICAL: When presenting this confirmation prompt to the user, you MUST output it as a direct plain text response and stop tool execution immediately. Do NOT call any command execution or interactive tools in the same turn, as unexpected tool calls may be auto-replied by the simulation harness and cause an infinite loop. Yield immediately for the user's reply.

Refer to Models Catalog for hardware recommendations for specific open models.

Resources

• Data Preparation Guide
• Models Catalog
• Tuning Guide
• scripts/prepare_dataset.py: Data conversion & validation.
• scripts/tune_open_model.py: Open model tuning job submission.