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A training run improves a base model through reinforcement learning. You provide the rollout, grader, training config, and dataset; Osmosis runs the job on managed training infrastructure, pulls code from your synced workspace repository, and records metrics, samples, logs, and any checkpoints the run produces.

Concepts

Training Configuration vs Training Run

A Training Configuration is the recipe: it identifies the model, dataset, AgentWorkflow, and training controls. A Training Run is one execution of that configuration. Submit the configuration again to run another experiment.

Train and Validation Split

Osmosis shuffles the selected dataset and holds out about 20% of the rows for validation. The validation count is rounded down and capped at 10,000 rows, so larger datasets keep more than 80% for training. The split is not configurable.

Submitting a Training Run

Submit a training run with a TOML configuration file:
Git Sync is the source of truth for your rollout code. The CLI reads config values from the local TOML file you pass, but rollout code comes from the synced workspace repository. Commit and push before submitting code changes. Set branch to use a pushed branch or commit_sha for a specific pushed revision; omit both to use the default branch.

Key Configuration Fields

branch and commit_sha are mutually exclusive. With branch, Osmosis resolves the branch head once at submission and stores that full commit SHA on the run. Omit both fields to use the repository’s default branch.
See Config Files for the full TOML reference. Submission validates the configuration against the shared schema and rejects unknown fields and out-of-range values; it does not check the configuration against the selected model or backend, so an unsupported combination can surface during provisioning or execution.

Status Lifecycle

A failed or crashed run can still have checkpoints saved before it ended. A single rollout failure does not necessarily fail the run: failed samples are excluded from training updates. Use Rollout Samples to inspect sample outcomes and Logs to diagnose repeated or run-level failures.

Monitoring

Platform Dashboard

Open Training Runs at platform.osmosis.ai to search and filter runs by status, dataset, base model, and rollout. The list also supports opening, renaming, stopping, and deleting runs when the corresponding action is available. Each run page has a sidebar with status, rollout-step progress, duration, examples processed, submission and timing details, dataset, base model, and rollout. Its tabs are:
  • Overview: six charts for Training Reward, Validation Reward, Model Entropy, Response Length, Total Length, and Truncation Ratio. Charts appear when the corresponding metric is available and can be refreshed or downloaded as CSV.
  • Rollout Samples: browse samples by rollout step, search them, compare their reward distribution, and inspect each sample’s input and output. This is the first place to check individual rollout failures.
  • Checkpoints: plot training reward against saved checkpoint steps and list each checkpoint’s name, step, and reward. You can rename checkpoints, download their artifacts, open their model page, and deploy or undeploy them when inference deployment is available.
  • Configuration: inspect the rollout, entrypoint, model, dataset, pinned branch or commit, resolved secret scopes, environment keys, and stored training config for the run.
  • Logs: follow lifecycle events and diagnostics from submission through completion or cleanup, and download them when needed.

CLI Commands

While a run is active, train info reports progress (current_step / total_steps) and the most recent reward. train list surfaces the same fields so you can scan runs at a glance.

LoRA Checkpoints

When the selected model and training backend support LoRA checkpoints, Osmosis saves them at the configured rollout-step cadence. A checkpoint captures the adapter weights at that point in training; a run is not guaranteed to produce a checkpoint if it ends before the first save or the selected training setup does not support one.

Managing Runs

Stopping a Run

This requests a graceful stop. The run is marked stopped once the platform accepts the cancellation; resource cleanup continues afterward and its progress appears in the run’s Logs.

Next Steps

CLI Training

Submit and manage training runs from a workspace repository.

Datasets

Upload datasets for training.

Models

Manage base models and deploy trained LoRA models.
Last modified on August 11, 2026