> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/tektoncd/pipeline/llms.txt
> Use this file to discover all available pages before exploring further.

# Simple Pipeline

> Creating a basic pipeline with multiple tasks

A pipeline chains together multiple tasks to create a workflow. This example shows a simple pipeline with dependent tasks.

## Example

```yaml theme={null}
apiVersion: tekton.dev/v1
kind: Task
metadata:
  name: add-task
spec:
  params:
    - name: first
      description: the first operand
    - name: second
      description: the second operand
  results:
    - name: sum
      description: the sum of the first and second operand
  steps:
    - name: add
      image: mirror.gcr.io/alpine
      env:
        - name: OP1
          value: $(params.first)
        - name: OP2
          value: $(params.second)
      command: ["/bin/sh", "-c"]
      args:
        - echo -n $((${OP1}+${OP2})) | tee $(results.sum.path);
---
apiVersion: tekton.dev/v1
kind: Pipeline
metadata:
  name: sum-three-pipeline
spec:
  params:
    - name: first
      description: the first operand
    - name: second
      description: the second operand
    - name: third
      description: the third operand
  tasks:
    - name: first-add
      taskRef:
        name: add-task
      params:
        - name: first
          value: $(params.first)
        - name: second
          value: $(params.second)
    - name: second-add
      taskRef:
        name: add-task
      params:
        - name: first
          value: $(tasks.first-add.results.sum)
        - name: second
          value: $(params.third)
  results:
    - name: sum
      description: the sum of all three operands
      value: $(tasks.second-add.results.sum)
    - name: partial-sum
      description: the sum of first two operands
      value: $(tasks.first-add.results.sum)
    - name: all-sum
      description: the sum of everything
      value: $(tasks.second-add.results.sum)-$(tasks.first-add.results.sum)
---
apiVersion: tekton.dev/v1
kind: PipelineRun
metadata:
  name: sum-three-pipeline-run
spec:
  pipelineRef:
    name: sum-three-pipeline
  params:
    - name: first
      value: "2"
    - name: second
      value: "10"
    - name: third
      value: "10"
```

## How It Works

<Steps>
  <Step title="First Task Executes">
    The `first-add` task runs first, adding the first two parameters (2 + 10 = 12) and emitting the result.
  </Step>

  <Step title="Second Task Uses First Task's Result">
    The `second-add` task automatically waits for `first-add` to complete because it references its result using `$(tasks.first-add.results.sum)`. It then adds this result to the third parameter (12 + 10 = 22).
  </Step>

  <Step title="Pipeline Results are Computed">
    After all tasks complete, the pipeline computes its own results by referencing task results. These become available in the PipelineRun status.
  </Step>
</Steps>

## Task Dependencies

Tekton automatically creates dependencies between tasks when:

* A task references another task's result: `$(tasks.TASK_NAME.results.RESULT_NAME)`
* A task explicitly uses `runAfter` to specify ordering

In this example, `second-add` implicitly depends on `first-add` because it uses its result.

## Expected Output

With the provided parameters (2, 10, 10):

* `first-add` outputs: 12
* `second-add` outputs: 22

Pipeline results:

```
sum: 22
partial-sum: 12
all-sum: 22-12
```

## Key Concepts

* **Pipeline**: A collection of tasks that execute in a defined order
* **Task References**: Use `taskRef` to reference an existing task by name
* **Implicit Dependencies**: Tasks automatically wait for tasks whose results they reference
* **Pipeline Results**: Pipelines can aggregate results from multiple tasks
* **Parameter Passing**: Pipeline parameters can be passed to tasks, and task results can be passed to other tasks

## Next Steps

* Learn about [pipelines with parameters](/examples/pipelines/pipeline-with-params)
* See [parallel task execution](/examples/pipelines/parallel-tasks)