Deploying and Evaluating Models on Agent Platform Endpoints

Reference for the deployment-and-endpoint-evaluation subset of the Quality Flywheel. Use this guide when the user needs to evaluate a model that is not yet served (must be deployed first) or is served on an Agent Platform endpoint rather than called through the agentplatform Python client directly.

The two scripts referenced here — scripts/endpoint_evaluation.py and scripts/maas_evaluation.py — wrap Stage 2 (inference) and Stage 3 (grading) of the Flywheel against deployed endpoints. They produce the same EvaluationResult shape consumed by scripts/inspect_results.py and scripts/compare_results.py, so the rest of the Flywheel (Stages 4 and 5) applies unchanged.

For the public-docs version of this workflow, see the Agent Platform model evaluation docs.

When to use this guide

The user wants to evaluate a custom-weights / Bring-Your-Own-Model (BYOM) model deployed to an Agent Platform endpoint.
The user wants to evaluate a Model-as-a-Service (MaaS) model (e.g. meta/llama3-8b, gemini-2.5-pro) by model ID.
The user is at the deploy-then-eval stage: weights exist in GCS or in Model Garden but no endpoint has been provisioned yet.

For agent (multi-turn) evaluation, dataset preparation, metric selection, failure clustering, or iteration, stay in the main SKILL.md flow. This guide only covers the deployment + endpoint-inference subset.

Setup

The deployment-eval dependencies are the same set the main SKILL.md relies on. Do not create a virtual environment — it starts empty and hides packages the environment already provides, forcing a redundant install. Probe, and install only what is missing:

python3 -c "import vertexai, google.genai, requests" \
  || pip install 'google-cloud-aiplatform[evaluation]>=1.163.0' 'google-genai>=1.0.0' requests

Keep the version specifiers quoted: unquoted, bash reads >=1.163.0 as a redirect and silently writes an empty file instead of constraining the install.

The scripts also shell out to gcloud and gsutil, so the user must have the Google Cloud SDK installed and gcloud auth application-default login completed.

Confirm project / region / quota project:

gcloud config get project
gcloud config get compute/region
gcloud config get billing/quota_project

1. Deploy a Model

[!TIP]

If the agent-platform-deploy skill is available, prefer it — it carries the full deployment surface. This section is the minimum needed to get an endpoint to evaluate against.

gcloud ai model-garden models deploy \
    --project=$PROJECT_ID \
    --region=$LOCATION_ID \
    --model=$MODEL \
    --machine-type=$MACHINE_TYPE \
    --accelerator-type=$ACCELERATOR_TYPE \
    --accelerator-count=$ACCELERATOR_COUNT \
    --endpoint-display-name=$ENDPOINT_NAME \
    --asynchronous

MODEL is either a Model Garden model ID (meta/llama3-8b) or a GCS URL to custom weights. If any of MACHINE_TYPE, ACCELERATOR_TYPE, ACCELERATOR_COUNT are missing, stop and ask the user — do not pick defaults silently. Confirm the full command with the user before running it.

Determining hardware requirements

For custom weights stored in GCS, check for a tuning marker first:

gcloud storage cat $GCS_URL/managed_oss_fine_tuning_marker.json
gcloud storage cat $GCS_URL/config.json

If neither is present, ask the user for the base model ID, then query recommended configs:

gcloud ai model-garden models list-deployment-config --model=$BASE_MODEL_ID

Summarize the recommended machine + accelerator combinations and confirm with the user before deploying.

2. Check Deploy Status

Deploys are asynchronous. Poll the operation:

gcloud ai operations describe $OPERATION_ID --region=$LOCATION_ID

Report the status to the user — including the "not found" case — without asking for confirmation first.

3. Run Inference and Evaluation

[!WARNING]

Both scripts use LLM-as-a-judge metrics. Tell the user up-front: this can take ~30 minutes per 50 samples.

If the scripts' imports (agentplatform) fail in the local environment, do not loop on pip install — fail fast and tell the user to install the deps from the Setup section above.

Dataset format: JSONL in GCS with a prompt field on each line. See dataset_schema.md for the per-metric column requirements. If the user's dataset doesn't have a prompt column, reformat it before running.

Recommended starter metrics (confirm with the user first):

coherence — does the response hold together logically?
fluency — grammatical correctness and natural flow.
text_quality — overall text quality.

For the full metric catalog, see metric_registry.md.

Suggest an experiment name based on ${MODEL_ID}_${DATASET_NAME} if the user doesn't provide one.

3.1. Bring-Your-Own-Model (BYOM) Endpoint

Inspect the endpoint first to confirm it exists and to capture the dedicatedEndpointDns (if dedicated) for the --dedicated_endpoint_dns flag:

gcloud ai endpoints describe $ENDPOINT_ID --region=$LOCATION_ID --project=$PROJECT_ID

If the endpoint ID or the dataset bucket doesn't exist, stop and ask the user for a valid value — don't propose a confirmation prompt with broken inputs.

python3 scripts/endpoint_evaluation.py \
    --project_id=$PROJECT_ID \
    --location=$LOCATION_ID \
    --endpoint_id=$ENDPOINT_ID \
    --dataset=gs://your-bucket/eval.jsonl \
    --metrics "GENERAL_QUALITY"

With a dedicated DNS:

python3 scripts/endpoint_evaluation.py \
    --project_id=$PROJECT_ID \
    --location=$LOCATION_ID \
    --endpoint_id=$ENDPOINT_ID \
    --dataset=gs://your-bucket/eval.jsonl \
    --dedicated_endpoint_dns=$DEDICATED_ENDPOINT_DNS \
    --metrics "GENERAL_QUALITY"

3.2. Model-as-a-Service (MaaS)

For MaaS models, no endpoint deploy is needed — call the model by ID:

python3 scripts/maas_evaluation.py \
    --project_id=$PROJECT_ID \
    --location=$LOCATION_ID \
    --model_id=$MAAS_MODEL_ID \
    --dataset=gs://your-bucket/eval.jsonl \
    --metrics "GENERAL_QUALITY"

Same input-validation rule as 3.1: if the bucket doesn't resolve, stop and ask the user.

4. Feed Results Back Into the Flywheel

Both scripts print summary_metrics and the first 5 rows of metrics_table. To persist the full result for Stage 4/5 analysis, capture the returned eval_result and serialize it the same way as the main SKILL.md "Always persist the result" block. Then:

scripts/inspect_results.py --failing-only for per-case triage.
scripts/compare_results.py --baseline <prev> --candidate <new> after a fix to confirm the target metric improved and nothing regressed.

The deployment workflow is only Stages 1–3 of the Flywheel. Stages 4 (Analyze Failures) and 5 (Optimize & Iterate) work identically whether the result came from a deployed endpoint, a MaaS model, or a direct client.evals.evaluate(...) call.

/agent-platform-eval-flywheel

referencesdeployment.md