diff --git a/cli/cliui/parameter.go b/cli/cliui/parameter.go
index 772b78cc55..9b3e9e47fb 100644
--- a/cli/cliui/parameter.go
+++ b/cli/cliui/parameter.go
@@ -69,7 +69,7 @@ func RichParameter(inv *serpent.Invocation, templateVersionParameter codersdk.Te
 		}
 	default:
 		text := "Enter a value"
-		if !templateVersionParameter.Required {
+		if defaultValue != "" {
 			text += fmt.Sprintf(" (default: %q)", defaultValue)
 		}
 		text += ":"
@@ -77,6 +77,10 @@ func RichParameter(inv *serpent.Invocation, templateVersionParameter codersdk.Te
 		value, err = Prompt(inv, PromptOptions{
 			Text: Bold(text),
 			Validate: func(value string) error {
+				// If empty, the default value will be used (if available).
+				if value == "" && defaultValue != "" {
+					value = defaultValue
+				}
 				return validateRichPrompt(value, templateVersionParameter)
 			},
 		})
diff --git a/cli/create.go b/cli/create.go
index 5b96652c44..c9da10f49d 100644
--- a/cli/create.go
+++ b/cli/create.go
@@ -323,6 +323,7 @@ func (r *RootCmd) Create(opts CreateOptions) *serpent.Command {
 				Action:            WorkspaceCreate,
 				TemplateVersionID: templateVersionID,
 				NewWorkspaceName:  workspaceName,
+				Owner:             workspaceOwner,
 
 				PresetParameters:      presetParameters,
 				RichParameterFile:     parameterFlags.richParameterFile,
@@ -456,6 +457,8 @@ type prepWorkspaceBuildArgs struct {
 	Action            WorkspaceCLIAction
 	TemplateVersionID uuid.UUID
 	NewWorkspaceName  string
+	// The owner is required when evaluating dynamic parameters
+	Owner string
 
 	LastBuildParameters       []codersdk.WorkspaceBuildParameter
 	SourceWorkspaceParameters []codersdk.WorkspaceBuildParameter
@@ -550,9 +553,14 @@ func prepWorkspaceBuild(inv *serpent.Invocation, client *codersdk.Client, args p
 		return nil, xerrors.Errorf("get template version: %w", err)
 	}
 
-	templateVersionParameters, err := client.TemplateVersionRichParameters(inv.Context(), templateVersion.ID)
-	if err != nil {
-		return nil, xerrors.Errorf("get template version rich parameters: %w", err)
+	dynamicParameters := true
+	if templateVersion.TemplateID != nil {
+		// TODO: This fetch is often redundant, as the caller often has the template already.
+		template, err := client.Template(ctx, *templateVersion.TemplateID)
+		if err != nil {
+			return nil, xerrors.Errorf("get template: %w", err)
+		}
+		dynamicParameters = !template.UseClassicParameterFlow
 	}
 
 	parameterFile := map[string]string{}
@@ -574,6 +582,45 @@ func prepWorkspaceBuild(inv *serpent.Invocation, client *codersdk.Client, args p
 		WithRichParametersFile(parameterFile).
 		WithRichParametersDefaults(args.RichParameterDefaults).
 		WithUseParameterDefaults(args.UseParameterDefaults)
+
+	var templateVersionParameters []codersdk.TemplateVersionParameter
+	if !dynamicParameters {
+		templateVersionParameters, err = client.TemplateVersionRichParameters(inv.Context(), templateVersion.ID)
+		if err != nil {
+			return nil, xerrors.Errorf("get template version rich parameters: %w", err)
+		}
+	} else {
+		var ownerID uuid.UUID
+		{ // Putting in its own block to limit scope of owningMember, as it might be nil
+			owningMember, err := client.OrganizationMember(ctx, templateVersion.OrganizationID.String(), args.Owner)
+			if err != nil {
+				// This is unfortunate, but if we are an org owner, then we can create workspaces
+				// for users that are not part of the organization.
+				owningUser, uerr := client.User(ctx, args.Owner)
+				if uerr != nil {
+					return nil, xerrors.Errorf("get owning member: %w", err)
+				}
+				ownerID = owningUser.ID
+			} else {
+				ownerID = owningMember.UserID
+			}
+		}
+
+		initial := make(map[string]string)
+		for _, v := range resolver.InitialValues() {
+			initial[v.Name] = v.Value
+		}
+
+		eval, err := client.EvaluateTemplateVersion(ctx, templateVersion.ID, ownerID, initial)
+		if err != nil {
+			return nil, xerrors.Errorf("evaluate template version dynamic parameters: %w", err)
+		}
+
+		for _, param := range eval.Parameters {
+			templateVersionParameters = append(templateVersionParameters, param.TemplateVersionParameter())
+		}
+	}
+
 	buildParameters, err := resolver.Resolve(inv, args.Action, templateVersionParameters)
 	if err != nil {
 		return nil, err
diff --git a/cli/create_test.go b/cli/create_test.go
index d80b8e56a5..e97539b195 100644
--- a/cli/create_test.go
+++ b/cli/create_test.go
@@ -24,6 +24,309 @@ import (
 	"github.com/coder/coder/v2/testutil"
 )
 
+func TestCreateDynamic(t *testing.T) {
+	t.Parallel()
+	owner := coderdtest.New(t, &coderdtest.Options{IncludeProvisionerDaemon: true})
+	first := coderdtest.CreateFirstUser(t, owner)
+	member, _ := coderdtest.CreateAnotherUser(t, owner, first.OrganizationID)
+
+	// Terraform template with conditional parameters.
+	// The "region" parameter only appears when "enable_region" is true.
+	const conditionalParamTF = `
+		terraform {
+		  required_providers {
+		    coder = {
+		      source = "coder/coder"
+		    }
+		  }
+		}
+		data "coder_workspace_owner" "me" {}
+		data "coder_parameter" "enable_region" {
+		  name         = "enable_region"
+		  order        = 1
+		  type         = "bool"
+		  default      = "false"
+		}
+		data "coder_parameter" "region" {
+		  name         = "region"
+		  count        = data.coder_parameter.enable_region.value == "true" ? 1 : 0
+		  order        = 2
+		  type         = "string"
+		  # No default - this makes it required when it appears
+		}
+	`
+
+	// Test conditional parameters: a parameter that only appears when another
+	// parameter has a certain value.
+	t.Run("ConditionalParam", func(t *testing.T) {
+		t.Parallel()
+		ctx := testutil.Context(t, testutil.WaitLong)
+		template, _ := coderdtest.DynamicParameterTemplate(t, owner, first.OrganizationID, coderdtest.DynamicParameterTemplateParams{
+			MainTF: conditionalParamTF,
+		})
+
+		// Test 1: Create without enabling region - region param should not exist
+		args := []string{
+			"create", "ws-no-region",
+			"--template", template.Name,
+			"--parameter", "enable_region=false",
+			"-y",
+		}
+		inv, root := clitest.New(t, args...)
+		clitest.SetupConfig(t, member, root)
+		pty := ptytest.New(t).Attach(inv)
+
+		doneChan := make(chan error)
+		go func() {
+			doneChan <- inv.Run()
+		}()
+
+		pty.ExpectMatchContext(ctx, "has been created")
+		err := testutil.RequireReceive(ctx, t, doneChan)
+		require.NoError(t, err)
+
+		// Verify workspace created with only enable_region parameter
+		ws, err := member.WorkspaceByOwnerAndName(t.Context(), codersdk.Me, "ws-no-region", codersdk.WorkspaceOptions{})
+		require.NoError(t, err)
+		buildParams, err := member.WorkspaceBuildParameters(t.Context(), ws.LatestBuild.ID)
+		require.NoError(t, err)
+		require.Len(t, buildParams, 1, "expected only enable_region parameter when enable_region=false")
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "enable_region", Value: "false"})
+
+		// Test 2: Create with region enabled - region param should exist
+		args = []string{
+			"create", "ws-with-region",
+			"--template", template.Name,
+			"--parameter", "enable_region=true",
+			"--parameter", "region=us-east",
+			"-y",
+		}
+		inv, root = clitest.New(t, args...)
+		clitest.SetupConfig(t, member, root)
+		pty = ptytest.New(t).Attach(inv)
+
+		doneChan = make(chan error)
+		go func() {
+			doneChan <- inv.Run()
+		}()
+
+		pty.ExpectMatchContext(ctx, "has been created")
+
+		err = testutil.RequireReceive(ctx, t, doneChan)
+		require.NoError(t, err)
+
+		// Verify workspace created with both parameters
+		ws, err = member.WorkspaceByOwnerAndName(t.Context(), codersdk.Me, "ws-with-region", codersdk.WorkspaceOptions{})
+		require.NoError(t, err)
+		buildParams, err = member.WorkspaceBuildParameters(t.Context(), ws.LatestBuild.ID)
+		require.NoError(t, err)
+		require.Len(t, buildParams, 2, "expected both enable_region and region parameters when enable_region=true")
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "enable_region", Value: "true"})
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "region", Value: "us-east"})
+	})
+
+	// Test that the CLI prompts for missing conditional parameters.
+	// When enable_region=true, the region parameter becomes required and CLI should prompt.
+	t.Run("PromptForConditionalParam", func(t *testing.T) {
+		t.Parallel()
+		ctx := testutil.Context(t, testutil.WaitLong)
+
+		template, _ := coderdtest.DynamicParameterTemplate(t, owner, first.OrganizationID, coderdtest.DynamicParameterTemplateParams{
+			MainTF: conditionalParamTF,
+		})
+
+		// Only provide enable_region=true, don't provide region - CLI should prompt for it
+		args := []string{
+			"create", "ws-prompted",
+			"--template", template.Name,
+			"--parameter", "enable_region=true",
+		}
+		inv, root := clitest.New(t, args...)
+		clitest.SetupConfig(t, member, root)
+		pty := ptytest.New(t).Attach(inv)
+
+		doneChan := make(chan error)
+		go func() {
+			doneChan <- inv.Run()
+		}()
+
+		// CLI should prompt for the region parameter since enable_region=true
+		pty.ExpectMatchContext(ctx, "region")
+		pty.WriteLine("eu-west")
+
+		// Confirm creation
+		pty.ExpectMatchContext(ctx, "Confirm create?")
+		pty.WriteLine("yes")
+
+		pty.ExpectMatchContext(ctx, "has been created")
+
+		err := <-doneChan
+		require.NoError(t, err)
+
+		// Verify workspace created with both parameters
+		ws, err := member.WorkspaceByOwnerAndName(t.Context(), codersdk.Me, "ws-prompted", codersdk.WorkspaceOptions{})
+		require.NoError(t, err)
+		buildParams, err := member.WorkspaceBuildParameters(t.Context(), ws.LatestBuild.ID)
+		require.NoError(t, err)
+		require.Len(t, buildParams, 2, "expected both enable_region and region parameters")
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "enable_region", Value: "true"})
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "region", Value: "eu-west"})
+	})
+
+	// Test that updating a template with a new required parameter causes start to fail
+	// when the user doesn't provide the new parameter value.
+	t.Run("UpdateTemplateRequiredParamStartFails", func(t *testing.T) {
+		t.Parallel()
+
+		// Initial template with just enable_region parameter (no default, so required)
+		const initialTF = `
+			terraform {
+			  required_providers {
+			    coder = {
+			      source = "coder/coder"
+			    }
+			  }
+			}
+			data "coder_workspace_owner" "me" {}
+			data "coder_parameter" "enable_region" {
+			  name         = "enable_region"
+			  type         = "bool"
+			}
+		`
+
+		template, _ := coderdtest.DynamicParameterTemplate(t, owner, first.OrganizationID, coderdtest.DynamicParameterTemplateParams{
+			MainTF: initialTF,
+		})
+
+		// Create workspace with initial template
+		inv, root := clitest.New(t, "create", "ws-update-test",
+			"--template", template.Name,
+			"--parameter", "enable_region=false",
+			"-y",
+		)
+		clitest.SetupConfig(t, member, root)
+		err := inv.Run()
+		require.NoError(t, err)
+
+		// Stop the workspace
+		inv, root = clitest.New(t, "stop", "ws-update-test", "-y")
+		clitest.SetupConfig(t, member, root)
+		err = inv.Run()
+		require.NoError(t, err)
+
+		const updatedTF = `
+			terraform {
+			  required_providers {
+			    coder = {
+			      source = "coder/coder"
+			    }
+			  }
+			}
+			data "coder_workspace_owner" "me" {}
+			data "coder_parameter" "enable_region" {
+			  name         = "enable_region"
+			  type         = "bool"
+			}
+			data "coder_parameter" "region" {
+			  count        = data.coder_parameter.enable_region.value == "true" ? 1 : 0
+			  name         = "region"
+			  type         = "string"
+			  # No default - required when enable_region is true
+			}
+		`
+
+		coderdtest.DynamicParameterTemplate(t, owner, first.OrganizationID, coderdtest.DynamicParameterTemplateParams{
+			MainTF:     updatedTF,
+			TemplateID: template.ID,
+		})
+
+		// Try to start the workspace with update - should fail because region is now required
+		// (enable_region defaults to true, making region appear, but no value provided)
+		// and we're using -y to skip prompts
+		inv, root = clitest.New(t, "start", "ws-update-test", "-y", "--parameter", "enable_region=true")
+		clitest.SetupConfig(t, member, root)
+		err = inv.Run()
+		require.Error(t, err, "start should fail because new required parameter 'region' is missing")
+		require.Contains(t, err.Error(), "region")
+	})
+
+	// Test that dynamic validation allows values that would be invalid with static validation.
+	// A slider's max value is determined by another parameter, so a value of 8 is invalid
+	// when max_slider=5, but valid when max_slider=10.
+	t.Run("DynamicValidation", func(t *testing.T) {
+		t.Parallel()
+		ctx := testutil.Context(t, testutil.WaitLong)
+
+		// Template where slider's max is controlled by another parameter
+		const dynamicValidationTF = `
+			terraform {
+			  required_providers {
+			    coder = {
+			      source = "coder/coder"
+			    }
+			  }
+			}
+			data "coder_workspace_owner" "me" {}
+			data "coder_parameter" "max_slider" {
+			  name         = "max_slider"
+			  type         = "number"
+			  default      = 5
+			}
+			data "coder_parameter" "slider" {
+			  name         = "slider"
+			  type         = "number"
+			  default      = 1
+			  validation {
+			    min = 1
+			    max = data.coder_parameter.max_slider.value
+			  }
+			}
+		`
+
+		template, _ := coderdtest.DynamicParameterTemplate(t, owner, first.OrganizationID, coderdtest.DynamicParameterTemplateParams{
+			MainTF: dynamicValidationTF,
+		})
+
+		// Test 1: slider=8 should fail when max_slider=5 (default)
+		inv, root := clitest.New(t, "create", "ws-validation-fail",
+			"--template", template.Name,
+			"--parameter", "slider=8",
+			"-y",
+		)
+		clitest.SetupConfig(t, member, root)
+		err := inv.Run()
+		require.Error(t, err, "slider=8 should fail when max_slider=5")
+
+		// Test 2: slider=8 should succeed when max_slider=10
+		inv, root = clitest.New(t, "create", "ws-validation-pass",
+			"--template", template.Name,
+			"--parameter", "max_slider=10",
+			"--parameter", "slider=8",
+			"-y",
+		)
+		clitest.SetupConfig(t, member, root)
+		pty := ptytest.New(t).Attach(inv)
+
+		doneChan := make(chan error)
+		go func() {
+			doneChan <- inv.Run()
+		}()
+
+		pty.ExpectMatchContext(ctx, "has been created")
+
+		err = <-doneChan
+		require.NoError(t, err, "slider=8 should succeed when max_slider=10")
+
+		// Verify workspace created with correct parameters
+		ws, err := member.WorkspaceByOwnerAndName(t.Context(), codersdk.Me, "ws-validation-pass", codersdk.WorkspaceOptions{})
+		require.NoError(t, err)
+		buildParams, err := member.WorkspaceBuildParameters(t.Context(), ws.LatestBuild.ID)
+		require.NoError(t, err)
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "max_slider", Value: "10"})
+		require.Contains(t, buildParams, codersdk.WorkspaceBuildParameter{Name: "slider", Value: "8"})
+	})
+}
+
 func TestCreate(t *testing.T) {
 	t.Parallel()
 	t.Run("Create", func(t *testing.T) {
diff --git a/cli/exp_scaletest.go b/cli/exp_scaletest.go
index 02bd80763a..1d124a2dcc 100644
--- a/cli/exp_scaletest.go
+++ b/cli/exp_scaletest.go
@@ -719,6 +719,7 @@ func (r *RootCmd) scaletestCreateWorkspaces() *serpent.Command {
 				Action:            WorkspaceCreate,
 				TemplateVersionID: tpl.ActiveVersionID,
 				NewWorkspaceName:  "scaletest-N", // TODO: the scaletest runner will pass in a different name here. Does this matter?
+				Owner:             codersdk.Me,
 
 				RichParameterFile: parameterFlags.richParameterFile,
 				RichParameters:    cliRichParameters,
@@ -1065,6 +1066,7 @@ func (r *RootCmd) scaletestWorkspaceUpdates() *serpent.Command {
 			richParameters, err := prepWorkspaceBuild(inv, client, prepWorkspaceBuildArgs{
 				Action:            WorkspaceCreate,
 				TemplateVersionID: tpl.ActiveVersionID,
+				Owner:             codersdk.Me,
 
 				RichParameterFile: parameterFlags.richParameterFile,
 				RichParameters:    cliRichParameters,
@@ -1786,6 +1788,7 @@ func (r *RootCmd) scaletestAutostart() *serpent.Command {
 			richParameters, err := prepWorkspaceBuild(inv, client, prepWorkspaceBuildArgs{
 				Action:            WorkspaceCreate,
 				TemplateVersionID: tpl.ActiveVersionID,
+				Owner:             codersdk.Me,
 
 				RichParameterFile: parameterFlags.richParameterFile,
 				RichParameters:    cliRichParameters,
diff --git a/cli/parameterresolver.go b/cli/parameterresolver.go
index aa239d85b6..fc5ebdd271 100644
--- a/cli/parameterresolver.go
+++ b/cli/parameterresolver.go
@@ -108,8 +108,8 @@ func (pr *ParameterResolver) Resolve(inv *serpent.Invocation, action WorkspaceCL
 
 	staged = pr.resolveWithParametersMapFile(staged)
 	staged = pr.resolveWithCommandLineOrEnv(staged)
-	staged = pr.resolveWithSourceBuildParameters(staged, templateVersionParameters)
-	staged = pr.resolveWithLastBuildParameters(staged, templateVersionParameters)
+	staged = pr.resolveWithSourceBuildParametersInParameters(staged, templateVersionParameters)
+	staged = pr.resolveWithLastBuildParametersInParameters(staged, templateVersionParameters)
 	staged = pr.resolveWithPreset(staged) // Preset parameters take precedence from all other parameters
 	if err = pr.verifyConstraints(staged, action, templateVersionParameters); err != nil {
 		return nil, err
@@ -120,6 +120,18 @@ func (pr *ParameterResolver) Resolve(inv *serpent.Invocation, action WorkspaceCL
 	return staged, nil
 }
 
+func (pr *ParameterResolver) InitialValues() []codersdk.WorkspaceBuildParameter {
+	var staged []codersdk.WorkspaceBuildParameter
+
+	staged = pr.resolveWithParametersMapFile(staged)
+	staged = pr.resolveWithCommandLineOrEnv(staged)
+	staged = pr.resolveWithSourceBuildParameters(staged)
+	staged = pr.resolveWithLastBuildParameters(staged)
+	staged = pr.resolveWithPreset(staged) // Preset parameters take precedence from all other parameters
+
+	return staged
+}
+
 func (pr *ParameterResolver) resolveWithPreset(resolved []codersdk.WorkspaceBuildParameter) []codersdk.WorkspaceBuildParameter {
 next:
 	for _, presetParameter := range pr.presetParameters {
@@ -180,7 +192,26 @@ nextEphemeralParameter:
 	return resolved
 }
 
-func (pr *ParameterResolver) resolveWithLastBuildParameters(resolved []codersdk.WorkspaceBuildParameter, templateVersionParameters []codersdk.TemplateVersionParameter) []codersdk.WorkspaceBuildParameter {
+func (pr *ParameterResolver) resolveWithLastBuildParameters(resolved []codersdk.WorkspaceBuildParameter) []codersdk.WorkspaceBuildParameter {
+	if pr.promptRichParameters {
+		return resolved // don't pull parameters from last build
+	}
+
+next:
+	for _, buildParameter := range pr.lastBuildParameters {
+		for i, r := range resolved {
+			if r.Name == buildParameter.Name {
+				resolved[i].Value = buildParameter.Value
+				continue next
+			}
+		}
+
+		resolved = append(resolved, buildParameter)
+	}
+	return resolved
+}
+
+func (pr *ParameterResolver) resolveWithLastBuildParametersInParameters(resolved []codersdk.WorkspaceBuildParameter, templateVersionParameters []codersdk.TemplateVersionParameter) []codersdk.WorkspaceBuildParameter {
 	if pr.promptRichParameters {
 		return resolved // don't pull parameters from last build
 	}
@@ -216,7 +247,22 @@ next:
 	return resolved
 }
 
-func (pr *ParameterResolver) resolveWithSourceBuildParameters(resolved []codersdk.WorkspaceBuildParameter, templateVersionParameters []codersdk.TemplateVersionParameter) []codersdk.WorkspaceBuildParameter {
+func (pr *ParameterResolver) resolveWithSourceBuildParameters(resolved []codersdk.WorkspaceBuildParameter) []codersdk.WorkspaceBuildParameter {
+next:
+	for _, buildParameter := range pr.sourceWorkspaceParameters {
+		for i, r := range resolved {
+			if r.Name == buildParameter.Name {
+				resolved[i].Value = buildParameter.Value
+				continue next
+			}
+		}
+
+		resolved = append(resolved, buildParameter)
+	}
+	return resolved
+}
+
+func (pr *ParameterResolver) resolveWithSourceBuildParametersInParameters(resolved []codersdk.WorkspaceBuildParameter, templateVersionParameters []codersdk.TemplateVersionParameter) []codersdk.WorkspaceBuildParameter {
 next:
 	for _, buildParameter := range pr.sourceWorkspaceParameters {
 		tvp := findTemplateVersionParameter(buildParameter, templateVersionParameters)
diff --git a/cli/start.go b/cli/start.go
index 28fc151206..e4e2bd40f3 100644
--- a/cli/start.go
+++ b/cli/start.go
@@ -152,6 +152,7 @@ func buildWorkspaceStartRequest(inv *serpent.Invocation, client *codersdk.Client
 		TemplateVersionID:   version,
 		NewWorkspaceName:    workspace.Name,
 		LastBuildParameters: lastBuildParameters,
+		Owner:               workspace.OwnerID.String(),
 
 		PromptEphemeralParameters: parameterFlags.promptEphemeralParameters,
 		EphemeralParameters:       ephemeralParameters,
diff --git a/cli/update_test.go b/cli/update_test.go
index b80218f49a..8f2ea97852 100644
--- a/cli/update_test.go
+++ b/cli/update_test.go
@@ -413,13 +413,13 @@ func TestUpdateValidateRichParameters(t *testing.T) {
 		}()
 
 		pty.ExpectMatch(stringParameterName)
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("$$")
 		pty.ExpectMatch("does not match")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
-		pty.WriteLine("")
+		pty.ExpectMatch("> Enter a value: ")
+		pty.WriteLine("ABC")
 		pty.ExpectMatch("does not match")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("abc")
 		_ = testutil.TryReceive(ctx, t, doneChan)
 	})
@@ -459,13 +459,13 @@ func TestUpdateValidateRichParameters(t *testing.T) {
 		}()
 
 		pty.ExpectMatch(numberParameterName)
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("12")
 		pty.ExpectMatch("is more than the maximum")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
-		pty.WriteLine("")
+		pty.ExpectMatch("> Enter a value: ")
+		pty.WriteLine("notanumber")
 		pty.ExpectMatch("is not a number")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("8")
 		_ = testutil.TryReceive(ctx, t, doneChan)
 	})
@@ -505,13 +505,13 @@ func TestUpdateValidateRichParameters(t *testing.T) {
 		}()
 
 		pty.ExpectMatch(boolParameterName)
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("cat")
 		pty.ExpectMatch("boolean value can be either \"true\" or \"false\"")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
-		pty.WriteLine("")
+		pty.ExpectMatch("> Enter a value: ")
+		pty.WriteLine("dog")
 		pty.ExpectMatch("boolean value can be either \"true\" or \"false\"")
-		pty.ExpectMatch("> Enter a value (default: \"\"): ")
+		pty.ExpectMatch("> Enter a value: ")
 		pty.WriteLine("false")
 		_ = testutil.TryReceive(ctx, t, doneChan)
 	})
diff --git a/codersdk/parameters.go b/codersdk/parameters.go
index 1e15d0496c..937fbe4005 100644
--- a/codersdk/parameters.go
+++ b/codersdk/parameters.go
@@ -7,6 +7,8 @@ import (
 	"github.com/google/uuid"
 	"golang.org/x/xerrors"
 
+	"github.com/coder/coder/v2/coderd/util/ptr"
+	"github.com/coder/coder/v2/coderd/util/slice"
 	"github.com/coder/coder/v2/codersdk/wsjson"
 	"github.com/coder/websocket"
 )
@@ -69,6 +71,54 @@ type PreviewParameter struct {
 	Diagnostics []FriendlyDiagnostic `json:"diagnostics"`
 }
 
+func (p PreviewParameter) TemplateVersionParameter() TemplateVersionParameter {
+	tp := TemplateVersionParameter{
+		Name:                 p.Name,
+		DisplayName:          p.DisplayName,
+		Description:          p.Description,
+		DescriptionPlaintext: p.Description,
+		Type:                 string(p.Type),
+		FormType:             string(p.FormType),
+		Mutable:              p.Mutable,
+		DefaultValue:         p.DefaultValue.Value,
+		Icon:                 p.Icon,
+		Options: slice.List(p.Options, func(o PreviewParameterOption) TemplateVersionParameterOption {
+			return o.TemplateVersionParameterOption()
+		}),
+		Required:  p.Required,
+		Ephemeral: p.Ephemeral,
+	}
+
+	if len(p.Validations) > 0 {
+		valid := p.Validations[0]
+		tp.ValidationError = valid.Error
+		if valid.Monotonic != nil {
+			tp.ValidationMonotonic = ValidationMonotonicOrder(*valid.Monotonic)
+		}
+		if valid.Regex != nil {
+			tp.ValidationRegex = *valid.Regex
+		}
+		if valid.Min != nil {
+			//nolint:gosec
+			tp.ValidationMin = ptr.Ref(int32(*valid.Min))
+		}
+		if valid.Max != nil {
+			//nolint:gosec
+			tp.ValidationMax = ptr.Ref(int32(*valid.Max))
+		}
+	}
+	return tp
+}
+
+func (o PreviewParameterOption) TemplateVersionParameterOption() TemplateVersionParameterOption {
+	return TemplateVersionParameterOption{
+		Name:        o.Name,
+		Description: o.Description,
+		Value:       o.Value.Value,
+		Icon:        o.Icon,
+	}
+}
+
 type PreviewParameterData struct {
 	Name         string                       `json:"name"`
 	DisplayName  string                       `json:"display_name"`
diff --git a/codersdk/richparameters.go b/codersdk/richparameters.go
index db109316fd..5df7d2bead 100644
--- a/codersdk/richparameters.go
+++ b/codersdk/richparameters.go
@@ -1,8 +1,12 @@
 package codersdk
 
 import (
+	"context"
 	"encoding/json"
+	"fmt"
+	"net/http"
 
+	"github.com/google/uuid"
 	"golang.org/x/xerrors"
 	"tailscale.com/types/ptr"
 
@@ -10,6 +14,26 @@ import (
 	"github.com/coder/terraform-provider-coder/v2/provider"
 )
 
+func (c *Client) EvaluateTemplateVersion(ctx context.Context, templateVersionID uuid.UUID, ownerID uuid.UUID, inputs map[string]string) (DynamicParametersResponse, error) {
+	res, err := c.Request(ctx, http.MethodPost,
+		fmt.Sprintf("/api/v2/templateversions/%s/dynamic-parameters/evaluate", templateVersionID),
+		DynamicParametersRequest{
+			ID:      0,
+			Inputs:  inputs,
+			OwnerID: ownerID,
+		})
+	if err != nil {
+		return DynamicParametersResponse{}, xerrors.Errorf("do request: %w", err)
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		return DynamicParametersResponse{}, ReadBodyAsError(res)
+	}
+
+	var dynResp DynamicParametersResponse
+	return dynResp, json.NewDecoder(res.Body).Decode(&dynResp)
+}
+
 func ValidateNewWorkspaceParameters(richParameters []TemplateVersionParameter, buildParameters []WorkspaceBuildParameter) error {
 	return ValidateWorkspaceBuildParameters(richParameters, buildParameters, nil)
 }