What is a sequential agent workflow?

A sequential agent workflow runs its steps one after another in a defined order. Each step completes before the next begins, and its output can become the next step's input. This is the simplest execution pattern for tasks with a clear dependency chain.

Example: Generating an API test suite

Consider an agent that creates tests for one endpoint:

1. Read requirements: Extract the endpoint's request parameters and expected behavior.
2. Generate tests: Use those requirements to produce test cases.
3. Validate tests: Check the test cases against the specification and required output schema.
4. Prepare a report: Present the validated results.

Execution flows as:

Read requirements → Generate tests → Validate tests → Prepare report

The validation step must receive the generated tests, so it cannot meaningfully finish before test generation.

How does it work?

• The orchestrator starts the first node with the initial workflow state.
• When the node completes successfully, its output is saved or merged into state.
• The next node reads the data it needs and performs its assigned operation.
• The sequence continues until the completion condition is met or the workflow stops safely.

For example, the test-generation node might produce a structured list of scenarios; the validation node consumes that list and reports any requirement gaps.

When is sequential execution a good fit?

• Strict dependencies: The next operation needs the previous operation's output.
• Ordered checks: Authorization or validation must happen before a consequential action.
• Simple pipelines: The task is predictable and does not benefit from parallel branches.
• Ease of debugging: A linear execution history makes it straightforward to identify the step that failed.

Advantages and limitations

Advantages: Simple to design, explain, test, and monitor. Shared-state updates are usually easier to reason about than concurrent writes.

Limitations: Independent tasks may wait unnecessarily, increasing total latency. A slow or blocked step delays every downstream step.

For example, if an agent already has a customer ID and needs both order and support histories, those independent lookups could run concurrently rather than one after another.

Sequential does not mean ignoring failures

A production workflow should validate required outputs at each boundary. If a step fails, downstream work should remain blocked until the system retries safely, recovers, or reports failure. A timed-out external action should be checked before another attempt to avoid duplicating side effects.

Sequential workflow vs. sequential planning

A sequential workflow describes how the system executes its nodes. A plan describes the actions selected for a particular goal. A sequential workflow may execute a fixed plan, while its individual nodes can still use an LLM to interpret information.

In short

Sequential agent workflows execute a chain of dependent tasks in order. They are a strong default for small, predictable processes, but can be combined with parallel or conditional execution when the task requires more flexibility.