> ## Documentation Index
> Fetch the complete documentation index at: https://docs.evolvingmachines.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Core concepts

> How a dataset becomes trials, rewards, analyses and results.

```mermaid theme={null}
%%{init: {"themeVariables": {"fontSize": "15px", "fontFamily": "Google Sans Flex, sans-serif"}, "flowchart": {"nodeSpacing": 24, "rankSpacing": 28, "padding": 10, "wrappingWidth": 170, "subGraphTitleMargin": {"top": 6, "bottom": 6}}}}%%
flowchart TB
  subgraph S[Set up]
    D[Dataset: a folder of tasks] --> J[Job: arms of harness x model, one sandbox provider]
    J --> T[Trials: one per task per arm]
  end
  subgraph RUN[Run, per trial]
    SB[Sandbox: the agent works on the task] --> V[Verifier: scores the result]
    SB -.-> L[Live trace to the dashboard]
    V --> R[Reward and outputs: trajectory, files, logs]
  end
  subgraph AFTER[After]
    AN[Analyze: trace analysis, verdicts]
    C[Check: task quality]
    O[Results: jobs, trials, analyses and checks, in the dashboard and as downloads]
  end
  T --> SB
  R --> AN
  D --> C
  R ~~~ C
  R --> O
  AN --> O
  C --> O
```

* **Dataset**: a named, versioned folder of tasks in the catalog. `name@version` names one version; a bare name means the active one.
* **Task**: one directory with an instruction, an environment, and a verifier. See [tasks](/core-concepts/tasks).
* **Job**: one run of every task of its datasets by every arm, a fixed number of attempts each. See [jobs](/core-concepts/jobs).
* **Arm**: one harness driving one model, with its optional effort, preset, config and skills. A job with two models has two arms, and every arm runs on the job's one sandbox provider.
* **Trial**: one attempt of one task by one arm, in its own sandbox. See [trials](/core-concepts/trials).
* **Trajectory**: the record of what the agent did: the instruction, every agent turn, every tool call and its result. It streams live to the dashboard while the trial runs and is stored with the trial.
* **Verifier**: the task's test script. It runs after the agent has finished and produces the reward.
* **Reward**: the verifier's score for the trial, usually `1` or `0`.
* **Outputs**: what a finished trial keeps: the reward, the trajectory, the agent's files and the logs, captured when the trial ends. See [trial outputs](/core-concepts/trial-outputs).
* **Analysis**: a rubric judgment of a settled trial's trace, one analyzer run per trial. See [analyze](/core-concepts/analyze).
* **Check**: a rubric judgment of a task itself, before you spend a job on it. See [check](/core-concepts/check).