scott-lowe-vapi · Oct 19, 2026
diff --git a/fern/docs.yml b/fern/docs.yml
@@ -689,6 +689,9 @@ navigation:
               - page: Quickstart
                 path: observability/simulations-quickstart.mdx
                 icon: fa-light fa-rocket
+              - page: Test an assistant
+                path: observability/simulations-test-tab.mdx
+                icon: fa-light fa-vial
               - page: Advanced
                 path: observability/simulations-advanced.mdx
                 icon: fa-light fa-flask-vial

diff --git a/fern/observability/simulations-quickstart.mdx b/fern/observability/simulations-quickstart.mdx
@@ -7,6 +7,8 @@ slug: observability/simulations-quickstart
 
 In about 10 minutes, you'll run an AI tester through an appointment-booking conversation with Riley and get a pass or fail result. You'll also have a reusable simulation suite that you can run again after any change.
 
+Testing a single assistant? Start from its [**Test tab**](/observability/simulations-test-tab), where Composer can generate a suite for you.
+
 ## What you'll build
 
 A reusable **simulation suite** that asks an AI tester to book an appointment with Riley, Vapi's appointment-scheduler template assistant. The first criterion checks whether Riley reports the requested date and time with a confirmation number. This is a conversation-only demonstration, not proof that an appointment exists in a calendar.

diff --git a/fern/observability/simulations-test-tab.mdx b/fern/observability/simulations-test-tab.mdx
@@ -0,0 +1,89 @@
+---
+title: Test an assistant
+subtitle: Generate, run, and track simulation suites from an assistant's Test tab
+description: "Use an assistant's Test tab to generate a simulation suite with Composer, run it, and follow its latest results and run history without leaving the assistant."
+slug: observability/simulations-test-tab
+---
+
+The **Test** tab on an assistant lists the [**simulation suites**](/observability/simulations-overview) assigned to it. From the tab, you can generate a suite with Composer, run or rerun a suite, and open its results and run history without leaving the assistant.
+
+## Prerequisites
+
+- An [**assistant**](/assistants) in your Vapi account.
+- Permission to read test suites and test runs. Without both, the **Test** tab does not appear.
+- Permission to create test suites to generate a suite, and permission to create test runs to run one.
+
+<Note>
+  Runs use the published version of the assistant. If you're editing a draft, the tab shows **Runs use the published version**. Publish your changes to test them. If [**traffic splitting**](/assistants/versioning/traffic-splitting) is enabled, publish the new version with 0% traffic so it handles no live calls.
+</Note>
+
+## Generate a suite with Composer
+
+Open the assistant and select the **Test** tab. If no suites are assigned to the assistant, the tab shows **No test suites yet** with **Generate with Composer** and an **About simulations** link. Once the assistant has suites, select **Generate suite** above the table to create another.
+
+{/* Screenshot: Test tab empty state with "No test suites yet" and the Generate with Composer button */}
+
+Both buttons open [**Composer**](/composer#generate-tests-for-an-assistant) in a new thread for this assistant:
+
+<Steps>
+  <Step title="Review the test requirements">
+    Composer reads the assistant's prompt and tools and drafts **Test requirements**. Select **Generate coverage** to accept them, or type the changes you want in the chat.
+  </Step>
+
+  <Step title="Review the generated suite">
+    Composer generates simulations from the requirements and saves them as a suite assigned to the assistant. The suite card shows **Saved to the Test tab**. Tools that reach your systems are mocked by default, and each simulation lists any tools it mocks.
+  </Step>
+
+  <Step title="Run the suite">
+    Select **Run suite** on the card to start a chat run with one iteration. The suite also appears in the **Test** tab.
+  </Step>
+</Steps>
+
+## Read the suite table
+
+The table shows up to 100 suites assigned to the assistant, one row per suite, with the latest run of that suite against this assistant.
+
+{/* Screenshot: Test tab suite table with Status, Progress, and Last run columns */}
+
+| Column | What it shows |
+| -- | -- |
+| **Test suites assigned** | The suite name. Once the suite has run, select the row to open its latest run. |
+| **Simulations** | How many simulations the latest run executed, with its chat or voice mode. Before the first run, the number of simulations in the suite. |
+| **Status** | The latest run's status: **Queued**, **Running**, **Passed**, **Failed**, **Errored**, or **Canceled**. A suite that has never run for this assistant shows **Not run yet**. |
+| **Progress** | A bar of the latest run's outcomes. During a run, it shows how many simulations are complete, such as `2 of 5 complete`. After the run, it summarizes the outcomes, such as `4 passed · 1 failed or errored`. |
+| **Last run** | When the latest run ended, such as `5 minutes ago`. It updates every minute while the tab is open. |
+
+Each row ends with a **Run** or **Rerun** button. Once a suite has run, the row also shows a run history button that opens **Simulations** > **Runs** filtered to that suite and this assistant. To see every run for the assistant, select **View run history** above the table.
+
+## Run a suite
+
+Select **Run** on a suite that has never run for this assistant. If the suite can run in chat, it starts immediately as a chat run with one iteration, and the row updates as it progresses.
+
+The **Run suite** dialog opens instead, so you can choose the mode and iterations, when:
+
+- The assistant needs voice, such as one that uses a GPT Live model. **Voice** is the only mode offered.
+- One of the suite's simulations is missing.
+- A scenario has hooks configured.
+
+To run a suite again, select **Rerun**. The dialog always opens so you can choose **Chat** or **Voice** and the number of **Iterations**. It starts with the mode of the previous run. Each rerun creates a new run and picks up any changes made to the suite.
+
+<Note>
+  A suite with no simulations can't run. Add at least one simulation before running it. Run and Rerun stay disabled while a run of the suite is queued or running.
+</Note>
+
+## Next steps
+
+<CardGroup cols={2}>
+  <Card title="Simulations quickstart" icon="rocket" href="/observability/simulations-quickstart">
+    Build and run a simulation suite step by step.
+  </Card>
+  <Card title="Manage simulations" icon="sliders" href="/observability/simulations-manage">
+    Edit suites, review results, and maintain coverage.
+  </Card>
+  <Card title="Mock tool responses" icon="flask" href="/observability/simulations-advanced#mock-tool-responses">
+    Control what tools return during a simulation.
+  </Card>
+  <Card title="Composer" icon="wand-magic-sparkles" href="/composer#generate-tests-for-an-assistant">
+    Generate tests for an assistant in conversation.
+  </Card>
+</CardGroup>