Part data model (#950)

9 files changed, 439 insertions, 362 deletions

diff --git a/packages/tui/sdk/.stats.yml b/packages/tui/sdk/.stats.yml
index 4449c4d95..61d2fa3b7 100644
--- a/packages/tui/sdk/.stats.yml
+++ b/packages/tui/sdk/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 22
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/opencode%2Fopencode-eb25bb3673f94d0e98a7036e2a2b0ed7ad63d1598665f2d5e091ec0835273798.yml
-openapi_spec_hash: 62f6a8a06aaa4f4ae13e85d56652724f
-config_hash: 589ec6a935a43a3c49a325ece86cbda2
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/opencode%2Fopencode-352994eb17f76d9472b0f0176efacf77a200a6fab2db28d1cfcd29451b211d7a.yml
+openapi_spec_hash: f01cd3de8c7cf0c9fd513896e81986de
+config_hash: 3695cfc829cfaae14490850b4a1ed282
diff --git a/packages/tui/sdk/README.md b/packages/tui/sdk/README.md
index 2b5782347..38840b28a 100644
--- a/packages/tui/sdk/README.md
+++ b/packages/tui/sdk/README.md
@@ -49,11 +49,14 @@ import (
 
 func main() {
 	client := opencode.NewClient()
-	events, err := client.Event.List(context.TODO())
+	stream := client.Event.ListStreaming(context.TODO())
+	for stream.Next() {
+		fmt.Printf("%+v\n", stream.Current())
+	}
+	err := stream.Err()
 	if err != nil {
 		panic(err.Error())
 	}
-	fmt.Printf("%+v\n", events)
 }
 
 ```
@@ -171,14 +174,14 @@ When the API returns a non-success status code, we return an error with type
 To handle errors, we recommend that you use the `errors.As` pattern:
 
 ```go
-_, err := client.Event.List(context.TODO())
-if err != nil {
+stream := client.Event.ListStreaming(context.TODO())
+if stream.Err() != nil {
 	var apierr *opencode.Error
-	if errors.As(err, &apierr) {
+	if errors.As(stream.Err(), &apierr) {
 		println(string(apierr.DumpRequest(true)))  // Prints the serialized HTTP request
 		println(string(apierr.DumpResponse(true))) // Prints the serialized HTTP response
 	}
-	panic(err.Error()) // GET "/event": 400 Bad Request { ... }
+	panic(stream.Err().Error()) // GET "/event": 400 Bad Request { ... }
 }
 ```
 
@@ -196,7 +199,7 @@ To set a per-retry timeout, use `option.WithRequestTimeout()`.
 // This sets the timeout for the request, including all the retries.
 ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
 defer cancel()
-client.Event.List(
+client.Event.ListStreaming(
 	ctx,
 	// This sets the per-retry timeout
 	option.WithRequestTimeout(20*time.Second),
@@ -231,7 +234,7 @@ client := opencode.NewClient(
 )
 
 // Override per-request:
-client.Event.List(context.TODO(), option.WithMaxRetries(5))
+client.Event.ListStreaming(context.TODO(), option.WithMaxRetries(5))
 ```
 
 ### Accessing raw response data (e.g. response headers)
@@ -242,8 +245,8 @@ you need to examine response headers, status codes, or other details.
 ```go
 // Create a variable to store the HTTP response
 var response *http.Response
-events, err := client.Event.List(context.TODO(), option.WithResponseInto(&response))
-if err != nil {
+stream := client.Event.ListStreaming(context.TODO(), option.WithResponseInto(&response))
+if stream.Err() != nil {
 	// handle error
 }
 fmt.Printf("%+v\n", events)
diff --git a/packages/tui/sdk/api.md b/packages/tui/sdk/api.md
index 15bdcfa93..a48e6d7f1 100644
--- a/packages/tui/sdk/api.md
+++ b/packages/tui/sdk/api.md
@@ -77,15 +77,15 @@ Params Types:
 
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#FilePartParam">FilePartParam</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#TextPartParam">TextPartParam</a>
-- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#UserMessagePartUnionParam">UserMessagePartUnionParam</a>
 
 Response Types:
 
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#AssistantMessage">AssistantMessage</a>
-- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#AssistantMessagePart">AssistantMessagePart</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#FilePart">FilePart</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Message">Message</a>
+- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Part">Part</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Session">Session</a>
+- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#StepFinishPart">StepFinishPart</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#StepStartPart">StepStartPart</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#TextPart">TextPart</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#ToolPart">ToolPart</a>
@@ -94,7 +94,7 @@ Response Types:
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#ToolStatePending">ToolStatePending</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#ToolStateRunning">ToolStateRunning</a>
 - <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#UserMessage">UserMessage</a>
-- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#UserMessagePart">UserMessagePart</a>
+- <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionMessagesResponse">SessionMessagesResponse</a>
 
 Methods:
 
@@ -104,7 +104,7 @@ Methods:
 - <code title="post /session/{id}/abort">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Abort">Abort</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>) (<a href="https://pkg.go.dev/builtin#bool">bool</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
 - <code title="post /session/{id}/message">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Chat">Chat</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>, body <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionChatParams">SessionChatParams</a>) (<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#AssistantMessage">AssistantMessage</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
 - <code title="post /session/{id}/init">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Init">Init</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>, body <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionInitParams">SessionInitParams</a>) (<a href="https://pkg.go.dev/builtin#bool">bool</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
-- <code title="get /session/{id}/message">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Messages">Messages</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>) ([]<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Message">Message</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
+- <code title="get /session/{id}/message">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Messages">Messages</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>) ([]<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionMessagesResponse">SessionMessagesResponse</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
 - <code title="post /session/{id}/share">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Share">Share</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>) (<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Session">Session</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
 - <code title="post /session/{id}/summarize">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Summarize">Summarize</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>, body <a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionSummarizeParams">SessionSummarizeParams</a>) (<a href="https://pkg.go.dev/builtin#bool">bool</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
 - <code title="delete /session/{id}/share">client.Session.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#SessionService.Unshare">Unshare</a>(ctx <a href="https://pkg.go.dev/context">context</a>.<a href="https://pkg.go.dev/context#Context">Context</a>, id <a href="https://pkg.go.dev/builtin#string">string</a>) (<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go">opencode</a>.<a href="https://pkg.go.dev/github.com/sst/opencode-sdk-go#Session">Session</a>, <a href="https://pkg.go.dev/builtin#error">error</a>)</code>
diff --git a/packages/tui/sdk/client_test.go b/packages/tui/sdk/client_test.go
index e75d64925..62222a465 100644
--- a/packages/tui/sdk/client_test.go
+++ b/packages/tui/sdk/client_test.go
@@ -38,7 +38,7 @@ func TestUserAgentHeader(t *testing.T) {
 			},
 		}),
 	)
-	client.Event.List(context.Background())
+	client.Event.ListStreaming(context.Background())
 	if userAgent != fmt.Sprintf("Opencode/Go %s", internal.PackageVersion) {
 		t.Errorf("Expected User-Agent to be correct, but got: %#v", userAgent)
 	}
@@ -61,7 +61,11 @@ func TestRetryAfter(t *testing.T) {
 			},
 		}),
 	)
-	_, err := client.Event.List(context.Background())
+	stream := client.Event.ListStreaming(context.Background())
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("Expected there to be a cancel error")
 	}
@@ -95,7 +99,11 @@ func TestDeleteRetryCountHeader(t *testing.T) {
 		}),
 		option.WithHeaderDel("X-Stainless-Retry-Count"),
 	)
-	_, err := client.Event.List(context.Background())
+	stream := client.Event.ListStreaming(context.Background())
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("Expected there to be a cancel error")
 	}
@@ -124,7 +132,11 @@ func TestOverwriteRetryCountHeader(t *testing.T) {
 		}),
 		option.WithHeader("X-Stainless-Retry-Count", "42"),
 	)
-	_, err := client.Event.List(context.Background())
+	stream := client.Event.ListStreaming(context.Background())
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("Expected there to be a cancel error")
 	}
@@ -152,7 +164,11 @@ func TestRetryAfterMs(t *testing.T) {
 			},
 		}),
 	)
-	_, err := client.Event.List(context.Background())
+	stream := client.Event.ListStreaming(context.Background())
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("Expected there to be a cancel error")
 	}
@@ -174,7 +190,11 @@ func TestContextCancel(t *testing.T) {
 	)
 	cancelCtx, cancel := context.WithCancel(context.Background())
 	cancel()
-	_, err := client.Event.List(cancelCtx)
+	stream := client.Event.ListStreaming(cancelCtx)
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("Expected there to be a cancel error")
 	}
@@ -193,7 +213,11 @@ func TestContextCancelDelay(t *testing.T) {
 	)
 	cancelCtx, cancel := context.WithTimeout(context.Background(), 2*time.Millisecond)
 	defer cancel()
-	_, err := client.Event.List(cancelCtx)
+	stream := client.Event.ListStreaming(cancelCtx)
+	for stream.Next() {
+		// ...
+	}
+	err := stream.Err()
 	if err == nil {
 		t.Error("expected there to be a cancel error")
 	}
@@ -218,7 +242,11 @@ func TestContextDeadline(t *testing.T) {
 				},
 			}),
 		)
-		_, err := client.Event.List(deadlineCtx)
+		stream := client.Event.ListStreaming(deadlineCtx)
+		for stream.Next() {
+			// ...
+		}
+		err := stream.Err()
 		if err == nil {
 			t.Error("expected there to be a deadline error")
 		}
diff --git a/packages/tui/sdk/event.go b/packages/tui/sdk/event.go
index 8bbf636c3..9002d2aac 100644
--- a/packages/tui/sdk/event.go
+++ b/packages/tui/sdk/event.go
@@ -610,18 +610,14 @@ func (r eventListResponseEventMessagePartUpdatedJSON) RawJSON() string {
 func (r EventListResponseEventMessagePartUpdated) implementsEventListResponse() {}
 
 type EventListResponseEventMessagePartUpdatedProperties struct {
-	MessageID string                                                 `json:"messageID,required"`
-	Part      AssistantMessagePart                                   `json:"part,required"`
-	SessionID string                                                 `json:"sessionID,required"`
-	JSON      eventListResponseEventMessagePartUpdatedPropertiesJSON `json:"-"`
+	Part Part                                                   `json:"part,required"`
+	JSON eventListResponseEventMessagePartUpdatedPropertiesJSON `json:"-"`
 }
 
 // eventListResponseEventMessagePartUpdatedPropertiesJSON contains the JSON
 // metadata for the struct [EventListResponseEventMessagePartUpdatedProperties]
 type eventListResponseEventMessagePartUpdatedPropertiesJSON struct {
-	MessageID   apijson.Field
 	Part        apijson.Field
-	SessionID   apijson.Field
 	raw         string
 	ExtraFields map[string]apijson.Field
 }
diff --git a/packages/tui/sdk/scripts/lint b/packages/tui/sdk/scripts/lint
index 9f37abf28..7e03a7beb 100755
--- a/packages/tui/sdk/scripts/lint
+++ b/packages/tui/sdk/scripts/lint
@@ -5,7 +5,7 @@ set -e
 cd "$(dirname "$0")/.."
 
 echo "==> Running Go build"
-go build .
+go build ./...
 
 echo "==> Checking tests compile"
-go test -run=^$ .
+go test -run=^$ ./...
diff --git a/packages/tui/sdk/session.go b/packages/tui/sdk/session.go
index 6321d1ff6..e76ab7f90 100644
--- a/packages/tui/sdk/session.go
+++ b/packages/tui/sdk/session.go
@@ -101,7 +101,7 @@ func (r *SessionService) Init(ctx context.Context, id string, body SessionInitPa
 }
 
 // List messages for a session
-func (r *SessionService) Messages(ctx context.Context, id string, opts ...option.RequestOption) (res *[]Message, err error) {
+func (r *SessionService) Messages(ctx context.Context, id string, opts ...option.RequestOption) (res *[]SessionMessagesResponse, err error) {
 	opts = append(r.Options[:], opts...)
 	if id == "" {
 		err = errors.New("missing required id parameter")
@@ -152,7 +152,6 @@ type AssistantMessage struct {
 	ID         string                 `json:"id,required"`
 	Cost       float64                `json:"cost,required"`
 	ModelID    string                 `json:"modelID,required"`
-	Parts      []AssistantMessagePart `json:"parts,required"`
 	Path       AssistantMessagePath   `json:"path,required"`
 	ProviderID string                 `json:"providerID,required"`
 	Role       AssistantMessageRole   `json:"role,required"`
@@ -171,7 +170,6 @@ type assistantMessageJSON struct {
 	ID          apijson.Field
 	Cost        apijson.Field
 	ModelID     apijson.Field
-	Parts       apijson.Field
 	Path        apijson.Field
 	ProviderID  apijson.Field
 	Role        apijson.Field
@@ -435,211 +433,23 @@ func (r AssistantMessageErrorName) IsKnown() bool {
 	return false
 }
 
-type AssistantMessagePart struct {
-	Type AssistantMessagePartType `json:"type,required"`
-	ID   string                   `json:"id"`
-	Cost float64                  `json:"cost"`
-	// This field can have the runtime type of [ToolPartState].
-	State     interface{} `json:"state"`
-	Synthetic bool        `json:"synthetic"`
-	Text      string      `json:"text"`
-	// This field can have the runtime type of
-	// [AssistantMessagePartStepFinishPartTokens].
-	Tokens interface{}              `json:"tokens"`
-	Tool   string                   `json:"tool"`
-	JSON   assistantMessagePartJSON `json:"-"`
-	union  AssistantMessagePartUnion
-}
-
-// assistantMessagePartJSON contains the JSON metadata for the struct
-// [AssistantMessagePart]
-type assistantMessagePartJSON struct {
-	Type        apijson.Field
-	ID          apijson.Field
-	Cost        apijson.Field
-	State       apijson.Field
-	Synthetic   apijson.Field
-	Text        apijson.Field
-	Tokens      apijson.Field
-	Tool        apijson.Field
-	raw         string
-	ExtraFields map[string]apijson.Field
-}
-
-func (r assistantMessagePartJSON) RawJSON() string {
-	return r.raw
-}
-
-func (r *AssistantMessagePart) UnmarshalJSON(data []byte) (err error) {
-	*r = AssistantMessagePart{}
-	err = apijson.UnmarshalRoot(data, &r.union)
-	if err != nil {
-		return err
-	}
-	return apijson.Port(r.union, &r)
-}
-
-// AsUnion returns a [AssistantMessagePartUnion] interface which you can cast to
-// the specific types for more type safety.
-//
-// Possible runtime types of the union are [TextPart], [ToolPart], [StepStartPart],
-// [AssistantMessagePartStepFinishPart].
-func (r AssistantMessagePart) AsUnion() AssistantMessagePartUnion {
-	return r.union
-}
-
-// Union satisfied by [TextPart], [ToolPart], [StepStartPart] or
-// [AssistantMessagePartStepFinishPart].
-type AssistantMessagePartUnion interface {
-	implementsAssistantMessagePart()
-}
-
-func init() {
-	apijson.RegisterUnion(
-		reflect.TypeOf((*AssistantMessagePartUnion)(nil)).Elem(),
-		"type",
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(TextPart{}),
-			DiscriminatorValue: "text",
-		},
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(ToolPart{}),
-			DiscriminatorValue: "tool",
-		},
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(StepStartPart{}),
-			DiscriminatorValue: "step-start",
-		},
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(AssistantMessagePartStepFinishPart{}),
-			DiscriminatorValue: "step-finish",
-		},
-	)
-}
-
-type AssistantMessagePartStepFinishPart struct {
-	Cost   float64                                  `json:"cost,required"`
-	Tokens AssistantMessagePartStepFinishPartTokens `json:"tokens,required"`
-	Type   AssistantMessagePartStepFinishPartType   `json:"type,required"`
-	JSON   assistantMessagePartStepFinishPartJSON   `json:"-"`
-}
-
-// assistantMessagePartStepFinishPartJSON contains the JSON metadata for the struct
-// [AssistantMessagePartStepFinishPart]
-type assistantMessagePartStepFinishPartJSON struct {
-	Cost        apijson.Field
-	Tokens      apijson.Field
-	Type        apijson.Field
-	raw         string
-	ExtraFields map[string]apijson.Field
-}
-
-func (r *AssistantMessagePartStepFinishPart) UnmarshalJSON(data []byte) (err error) {
-	return apijson.UnmarshalRoot(data, r)
-}
-
-func (r assistantMessagePartStepFinishPartJSON) RawJSON() string {
-	return r.raw
-}
-
-func (r AssistantMessagePartStepFinishPart) implementsAssistantMessagePart() {}
-
-type AssistantMessagePartStepFinishPartTokens struct {
-	Cache     AssistantMessagePartStepFinishPartTokensCache `json:"cache,required"`
-	Input     float64                                       `json:"input,required"`
-	Output    float64                                       `json:"output,required"`
-	Reasoning float64                                       `json:"reasoning,required"`
-	JSON      assistantMessagePartStepFinishPartTokensJSON  `json:"-"`
-}
-
-// assistantMessagePartStepFinishPartTokensJSON contains the JSON metadata for the
-// struct [AssistantMessagePartStepFinishPartTokens]
-type assistantMessagePartStepFinishPartTokensJSON struct {
-	Cache       apijson.Field
-	Input       apijson.Field
-	Output      apijson.Field
-	Reasoning   apijson.Field
-	raw         string
-	ExtraFields map[string]apijson.Field
-}
-
-func (r *AssistantMessagePartStepFinishPartTokens) UnmarshalJSON(data []byte) (err error) {
-	return apijson.UnmarshalRoot(data, r)
-}
-
-func (r assistantMessagePartStepFinishPartTokensJSON) RawJSON() string {
-	return r.raw
-}
-
-type AssistantMessagePartStepFinishPartTokensCache struct {
-	Read  float64                                           `json:"read,required"`
-	Write float64                                           `json:"write,required"`
-	JSON  assistantMessagePartStepFinishPartTokensCacheJSON `json:"-"`
-}
-
-// assistantMessagePartStepFinishPartTokensCacheJSON contains the JSON metadata for
-// the struct [AssistantMessagePartStepFinishPartTokensCache]
-type assistantMessagePartStepFinishPartTokensCacheJSON struct {
-	Read        apijson.Field
-	Write       apijson.Field
-	raw         string
-	ExtraFields map[string]apijson.Field
-}
-
-func (r *AssistantMessagePartStepFinishPartTokensCache) UnmarshalJSON(data []byte) (err error) {
-	return apijson.UnmarshalRoot(data, r)
-}
-
-func (r assistantMessagePartStepFinishPartTokensCacheJSON) RawJSON() string {
-	return r.raw
-}
-
-type AssistantMessagePartStepFinishPartType string
-
-const (
-	AssistantMessagePartStepFinishPartTypeStepFinish AssistantMessagePartStepFinishPartType = "step-finish"
-)
-
-func (r AssistantMessagePartStepFinishPartType) IsKnown() bool {
-	switch r {
-	case AssistantMessagePartStepFinishPartTypeStepFinish:
-		return true
-	}
-	return false
-}
-
-type AssistantMessagePartType string
-
-const (
-	AssistantMessagePartTypeText       AssistantMessagePartType = "text"
-	AssistantMessagePartTypeTool       AssistantMessagePartType = "tool"
-	AssistantMessagePartTypeStepStart  AssistantMessagePartType = "step-start"
-	AssistantMessagePartTypeStepFinish AssistantMessagePartType = "step-finish"
-)
-
-func (r AssistantMessagePartType) IsKnown() bool {
-	switch r {
-	case AssistantMessagePartTypeText, AssistantMessagePartTypeTool, AssistantMessagePartTypeStepStart, AssistantMessagePartTypeStepFinish:
-		return true
-	}
-	return false
-}
-
 type FilePart struct {
-	Mime     string       `json:"mime,required"`
-	Type     FilePartType `json:"type,required"`
-	URL      string       `json:"url,required"`
-	Filename string       `json:"filename"`
-	JSON     filePartJSON `json:"-"`
+	ID        string       `json:"id,required"`
+	MessageID string       `json:"messageID,required"`
+	Mime      string       `json:"mime,required"`
+	SessionID string       `json:"sessionID,required"`
+	Type      FilePartType `json:"type,required"`
+	URL       string       `json:"url,required"`
+	Filename  string       `json:"filename"`
+	JSON      filePartJSON `json:"-"`
 }
 
 // filePartJSON contains the JSON metadata for the struct [FilePart]
 type filePartJSON struct {
+	ID          apijson.Field
+	MessageID   apijson.Field
 	Mime        apijson.Field
+	SessionID   apijson.Field
 	Type        apijson.Field
 	URL         apijson.Field
 	Filename    apijson.Field
@@ -655,7 +465,7 @@ func (r filePartJSON) RawJSON() string {
 	return r.raw
 }
 
-func (r FilePart) implementsUserMessagePart() {}
+func (r FilePart) implementsPart() {}
 
 type FilePartType string
 
@@ -672,23 +482,23 @@ func (r FilePartType) IsKnown() bool {
 }
 
 type FilePartParam struct {
-	Mime     param.Field[string]       `json:"mime,required"`
-	Type     param.Field[FilePartType] `json:"type,required"`
-	URL      param.Field[string]       `json:"url,required"`
-	Filename param.Field[string]       `json:"filename"`
+	ID        param.Field[string]       `json:"id,required"`
+	MessageID param.Field[string]       `json:"messageID,required"`
+	Mime      param.Field[string]       `json:"mime,required"`
+	SessionID param.Field[string]       `json:"sessionID,required"`
+	Type      param.Field[FilePartType] `json:"type,required"`
+	URL       param.Field[string]       `json:"url,required"`
+	Filename  param.Field[string]       `json:"filename"`
 }
 
 func (r FilePartParam) MarshalJSON() (data []byte, err error) {
 	return apijson.MarshalRoot(r)
 }
 
-func (r FilePartParam) implementsUserMessagePartUnionParam() {}
+func (r FilePartParam) implementsSessionChatParamsPartUnion() {}
 
 type Message struct {
-	ID string `json:"id,required"`
-	// This field can have the runtime type of [[]UserMessagePart],
-	// [[]AssistantMessagePart].
-	Parts     interface{} `json:"parts,required"`
+	ID        string      `json:"id,required"`
 	Role      MessageRole `json:"role,required"`
 	SessionID string      `json:"sessionID,required"`
 	// This field can have the runtime type of [UserMessageTime],
@@ -713,7 +523,6 @@ type Message struct {
 // messageJSON contains the JSON metadata for the struct [Message]
 type messageJSON struct {
 	ID          apijson.Field
-	Parts       apijson.Field
 	Role        apijson.Field
 	SessionID   apijson.Field
 	Time        apijson.Field
@@ -787,6 +596,128 @@ func (r MessageRole) IsKnown() bool {
 	return false
 }
 
+type Part struct {
+	ID        string   `json:"id,required"`
+	MessageID string   `json:"messageID,required"`
+	SessionID string   `json:"sessionID,required"`
+	Type      PartType `json:"type,required"`
+	CallID    string   `json:"callID"`
+	Cost      float64  `json:"cost"`
+	Filename  string   `json:"filename"`
+	Mime      string   `json:"mime"`
+	// This field can have the runtime type of [ToolPartState].
+	State     interface{} `json:"state"`
+	Synthetic bool        `json:"synthetic"`
+	Text      string      `json:"text"`
+	// This field can have the runtime type of [TextPartTime].
+	Time interface{} `json:"time"`
+	// This field can have the runtime type of [StepFinishPartTokens].
+	Tokens interface{} `json:"tokens"`
+	Tool   string      `json:"tool"`
+	URL    string      `json:"url"`
+	JSON   partJSON    `json:"-"`
+	union  PartUnion
+}
+
+// partJSON contains the JSON metadata for the struct [Part]
+type partJSON struct {
+	ID          apijson.Field
+	MessageID   apijson.Field
+	SessionID   apijson.Field
+	Type        apijson.Field
+	CallID      apijson.Field
+	Cost        apijson.Field
+	Filename    apijson.Field
+	Mime        apijson.Field
+	State       apijson.Field
+	Synthetic   apijson.Field
+	Text        apijson.Field
+	Time        apijson.Field
+	Tokens      apijson.Field
+	Tool        apijson.Field
+	URL         apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r partJSON) RawJSON() string {
+	return r.raw
+}
+
+func (r *Part) UnmarshalJSON(data []byte) (err error) {
+	*r = Part{}
+	err = apijson.UnmarshalRoot(data, &r.union)
+	if err != nil {
+		return err
+	}
+	return apijson.Port(r.union, &r)
+}
+
+// AsUnion returns a [PartUnion] interface which you can cast to the specific types
+// for more type safety.
+//
+// Possible runtime types of the union are [TextPart], [FilePart], [ToolPart],
+// [StepStartPart], [StepFinishPart].
+func (r Part) AsUnion() PartUnion {
+	return r.union
+}
+
+// Union satisfied by [TextPart], [FilePart], [ToolPart], [StepStartPart] or
+// [StepFinishPart].
+type PartUnion interface {
+	implementsPart()
+}
+
+func init() {
+	apijson.RegisterUnion(
+		reflect.TypeOf((*PartUnion)(nil)).Elem(),
+		"type",
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(TextPart{}),
+			DiscriminatorValue: "text",
+		},
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(FilePart{}),
+			DiscriminatorValue: "file",
+		},
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(ToolPart{}),
+			DiscriminatorValue: "tool",
+		},
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(StepStartPart{}),
+			DiscriminatorValue: "step-start",
+		},
+		apijson.UnionVariant{
+			TypeFilter:         gjson.JSON,
+			Type:               reflect.TypeOf(StepFinishPart{}),
+			DiscriminatorValue: "step-finish",
+		},
+	)
+}
+
+type PartType string
+
+const (
+	PartTypeText       PartType = "text"
+	PartTypeFile       PartType = "file"
+	PartTypeTool       PartType = "tool"
+	PartTypeStepStart  PartType = "step-start"
+	PartTypeStepFinish PartType = "step-finish"
+)
+
+func (r PartType) IsKnown() bool {
+	switch r {
+	case PartTypeText, PartTypeFile, PartTypeTool, PartTypeStepStart, PartTypeStepFinish:
+		return true
+	}
+	return false
+}
+
 type Session struct {
 	ID       string        `json:"id,required"`
 	Time     SessionTime   `json:"time,required"`
@@ -885,13 +816,115 @@ func (r sessionShareJSON) RawJSON() string {
 	return r.raw
 }
 
+type StepFinishPart struct {
+	ID        string               `json:"id,required"`
+	Cost      float64              `json:"cost,required"`
+	MessageID string               `json:"messageID,required"`
+	SessionID string               `json:"sessionID,required"`
+	Tokens    StepFinishPartTokens `json:"tokens,required"`
+	Type      StepFinishPartType   `json:"type,required"`
+	JSON      stepFinishPartJSON   `json:"-"`
+}
+
+// stepFinishPartJSON contains the JSON metadata for the struct [StepFinishPart]
+type stepFinishPartJSON struct {
+	ID          apijson.Field
+	Cost        apijson.Field
+	MessageID   apijson.Field
+	SessionID   apijson.Field
+	Tokens      apijson.Field
+	Type        apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *StepFinishPart) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r stepFinishPartJSON) RawJSON() string {
+	return r.raw
+}
+
+func (r StepFinishPart) implementsPart() {}
+
+type StepFinishPartTokens struct {
+	Cache     StepFinishPartTokensCache `json:"cache,required"`
+	Input     float64                   `json:"input,required"`
+	Output    float64                   `json:"output,required"`
+	Reasoning float64                   `json:"reasoning,required"`
+	JSON      stepFinishPartTokensJSON  `json:"-"`
+}
+
+// stepFinishPartTokensJSON contains the JSON metadata for the struct
+// [StepFinishPartTokens]
+type stepFinishPartTokensJSON struct {
+	Cache       apijson.Field
+	Input       apijson.Field
+	Output      apijson.Field
+	Reasoning   apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *StepFinishPartTokens) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r stepFinishPartTokensJSON) RawJSON() string {
+	return r.raw
+}
+
+type StepFinishPartTokensCache struct {
+	Read  float64                       `json:"read,required"`
+	Write float64                       `json:"write,required"`
+	JSON  stepFinishPartTokensCacheJSON `json:"-"`
+}
+
+// stepFinishPartTokensCacheJSON contains the JSON metadata for the struct
+// [StepFinishPartTokensCache]
+type stepFinishPartTokensCacheJSON struct {
+	Read        apijson.Field
+	Write       apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *StepFinishPartTokensCache) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r stepFinishPartTokensCacheJSON) RawJSON() string {
+	return r.raw
+}
+
+type StepFinishPartType string
+
+const (
+	StepFinishPartTypeStepFinish StepFinishPartType = "step-finish"
+)
+
+func (r StepFinishPartType) IsKnown() bool {
+	switch r {
+	case StepFinishPartTypeStepFinish:
+		return true
+	}
+	return false
+}
+
 type StepStartPart struct {
-	Type StepStartPartType `json:"type,required"`
-	JSON stepStartPartJSON `json:"-"`
+	ID        string            `json:"id,required"`
+	MessageID string            `json:"messageID,required"`
+	SessionID string            `json:"sessionID,required"`
+	Type      StepStartPartType `json:"type,required"`
+	JSON      stepStartPartJSON `json:"-"`
 }
 
 // stepStartPartJSON contains the JSON metadata for the struct [StepStartPart]
 type stepStartPartJSON struct {
+	ID          apijson.Field
+	MessageID   apijson.Field
+	SessionID   apijson.Field
 	Type        apijson.Field
 	raw         string
 	ExtraFields map[string]apijson.Field
@@ -905,7 +938,7 @@ func (r stepStartPartJSON) RawJSON() string {
 	return r.raw
 }
 
-func (r StepStartPart) implementsAssistantMessagePart() {}
+func (r StepStartPart) implementsPart() {}
 
 type StepStartPartType string
 
@@ -922,17 +955,25 @@ func (r StepStartPartType) IsKnown() bool {
 }
 
 type TextPart struct {
+	ID        string       `json:"id,required"`
+	MessageID string       `json:"messageID,required"`
+	SessionID string       `json:"sessionID,required"`
 	Text      string       `json:"text,required"`
 	Type      TextPartType `json:"type,required"`
 	Synthetic bool         `json:"synthetic"`
+	Time      TextPartTime `json:"time"`
 	JSON      textPartJSON `json:"-"`
 }
 
 // textPartJSON contains the JSON metadata for the struct [TextPart]
 type textPartJSON struct {
+	ID          apijson.Field
+	MessageID   apijson.Field
+	SessionID   apijson.Field
 	Text        apijson.Field
 	Type        apijson.Field
 	Synthetic   apijson.Field
+	Time        apijson.Field
 	raw         string
 	ExtraFields map[string]apijson.Field
 }
@@ -945,9 +986,7 @@ func (r textPartJSON) RawJSON() string {
 	return r.raw
 }
 
-func (r TextPart) implementsAssistantMessagePart() {}
-
-func (r TextPart) implementsUserMessagePart() {}
+func (r TextPart) implementsPart() {}
 
 type TextPartType string
 
@@ -963,29 +1002,70 @@ func (r TextPartType) IsKnown() bool {
 	return false
 }
 
+type TextPartTime struct {
+	Start float64          `json:"start,required"`
+	End   float64          `json:"end"`
+	JSON  textPartTimeJSON `json:"-"`
+}
+
+// textPartTimeJSON contains the JSON metadata for the struct [TextPartTime]
+type textPartTimeJSON struct {
+	Start       apijson.Field
+	End         apijson.Field
+	raw         string
+	ExtraFields map[string]apijson.Field
+}
+
+func (r *TextPartTime) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r textPartTimeJSON) RawJSON() string {
+	return r.raw
+}
+
 type TextPartParam struct {
-	Text      param.Field[string]       `json:"text,required"`
-	Type      param.Field[TextPartType] `json:"type,required"`
-	Synthetic param.Field[bool]         `json:"synthetic"`
+	ID        param.Field[string]            `json:"id,required"`
+	MessageID param.Field[string]            `json:"messageID,required"`
+	SessionID param.Field[string]            `json:"sessionID,required"`
+	Text      param.Field[string]            `json:"text,required"`
+	Type      param.Field[TextPartType]      `json:"type,required"`
+	Synthetic param.Field[bool]              `json:"synthetic"`
+	Time      param.Field[TextPartTimeParam] `json:"time"`
 }
 
 func (r TextPartParam) MarshalJSON() (data []byte, err error) {
 	return apijson.MarshalRoot(r)
 }
 
-func (r TextPartParam) implementsUserMessagePartUnionParam() {}
+func (r TextPartParam) implementsSessionChatParamsPartUnion() {}
+
+type TextPartTimeParam struct {
+	Start param.Field[float64] `json:"start,required"`
+	End   param.Field[float64] `json:"end"`
+}
+
+func (r TextPartTimeParam) MarshalJSON() (data []byte, err error) {
+	return apijson.MarshalRoot(r)
+}
 
 type ToolPart struct {
-	ID    string        `json:"id,required"`
-	State ToolPartState `json:"state,required"`
-	Tool  string        `json:"tool,required"`
-	Type  ToolPartType  `json:"type,required"`
-	JSON  toolPartJSON  `json:"-"`
+	ID        string        `json:"id,required"`
+	CallID    string        `json:"callID,required"`
+	MessageID string        `json:"messageID,required"`
+	SessionID string        `json:"sessionID,required"`
+	State     ToolPartState `json:"state,required"`
+	Tool      string        `json:"tool,required"`
+	Type      ToolPartType  `json:"type,required"`
+	JSON      toolPartJSON  `json:"-"`
 }
 
 // toolPartJSON contains the JSON metadata for the struct [ToolPart]
 type toolPartJSON struct {
 	ID          apijson.Field
+	CallID      apijson.Field
+	MessageID   apijson.Field
+	SessionID   apijson.Field
 	State       apijson.Field
 	Tool        apijson.Field
 	Type        apijson.Field
@@ -1001,7 +1081,7 @@ func (r toolPartJSON) RawJSON() string {
 	return r.raw
 }
 
-func (r ToolPart) implementsAssistantMessagePart() {}
+func (r ToolPart) implementsPart() {}
 
 type ToolPartState struct {
 	Status ToolPartStateStatus `json:"status,required"`
@@ -1357,18 +1437,16 @@ func (r toolStateRunningTimeJSON) RawJSON() string {
 }
 
 type UserMessage struct {
-	ID        string            `json:"id,required"`
-	Parts     []UserMessagePart `json:"parts,required"`
-	Role      UserMessageRole   `json:"role,required"`
-	SessionID string            `json:"sessionID,required"`
-	Time      UserMessageTime   `json:"time,required"`
-	JSON      userMessageJSON   `json:"-"`
+	ID        string          `json:"id,required"`
+	Role      UserMessageRole `json:"role,required"`
+	SessionID string          `json:"sessionID,required"`
+	Time      UserMessageTime `json:"time,required"`
+	JSON      userMessageJSON `json:"-"`
 }
 
 // userMessageJSON contains the JSON metadata for the struct [UserMessage]
 type userMessageJSON struct {
 	ID          apijson.Field
-	Parts       apijson.Field
 	Role        apijson.Field
 	SessionID   apijson.Field
 	Time        apijson.Field
@@ -1420,119 +1498,82 @@ func (r userMessageTimeJSON) RawJSON() string {
 	return r.raw
 }
 
-type UserMessagePart struct {
-	Type      UserMessagePartType `json:"type,required"`
-	Filename  string              `json:"filename"`
-	Mime      string              `json:"mime"`
-	Synthetic bool                `json:"synthetic"`
-	Text      string              `json:"text"`
-	URL       string              `json:"url"`
-	JSON      userMessagePartJSON `json:"-"`
-	union     UserMessagePartUnion
+type SessionMessagesResponse struct {
+	Info  Message                     `json:"info,required"`
+	Parts []Part                      `json:"parts,required"`
+	JSON  sessionMessagesResponseJSON `json:"-"`
 }
 
-// userMessagePartJSON contains the JSON metadata for the struct [UserMessagePart]
-type userMessagePartJSON struct {
-	Type        apijson.Field
-	Filename    apijson.Field
-	Mime        apijson.Field
-	Synthetic   apijson.Field
-	Text        apijson.Field
-	URL         apijson.Field
+// sessionMessagesResponseJSON contains the JSON metadata for the struct
+// [SessionMessagesResponse]
+type sessionMessagesResponseJSON struct {
+	Info        apijson.Field
+	Parts       apijson.Field
 	raw         string
 	ExtraFields map[string]apijson.Field
 }
 
-func (r userMessagePartJSON) RawJSON() string {
+func (r *SessionMessagesResponse) UnmarshalJSON(data []byte) (err error) {
+	return apijson.UnmarshalRoot(data, r)
+}
+
+func (r sessionMessagesResponseJSON) RawJSON() string {
 	return r.raw
 }
 
-func (r *UserMessagePart) UnmarshalJSON(data []byte) (err error) {
-	*r = UserMessagePart{}
-	err = apijson.UnmarshalRoot(data, &r.union)
-	if err != nil {
-		return err
-	}
-	return apijson.Port(r.union, &r)
+type SessionChatParams struct {
+	MessageID  param.Field[string]                       `json:"messageID,required"`
+	Mode       param.Field[string]                       `json:"mode,required"`
+	ModelID    param.Field[string]                       `json:"modelID,required"`
+	Parts      param.Field[[]SessionChatParamsPartUnion] `json:"parts,required"`
+	ProviderID param.Field[string]                       `json:"providerID,required"`
 }
 
-// AsUnion returns a [UserMessagePartUnion] interface which you can cast to the
-// specific types for more type safety.
-//
-// Possible runtime types of the union are [TextPart], [FilePart].
-func (r UserMessagePart) AsUnion() UserMessagePartUnion {
-	return r.union
+func (r SessionChatParams) MarshalJSON() (data []byte, err error) {
+	return apijson.MarshalRoot(r)
 }
 
-// Union satisfied by [TextPart] or [FilePart].
-type UserMessagePartUnion interface {
-	implementsUserMessagePart()
+type SessionChatParamsPart struct {
+	ID        param.Field[string]                     `json:"id,required"`
+	MessageID param.Field[string]                     `json:"messageID,required"`
+	SessionID param.Field[string]                     `json:"sessionID,required"`
+	Type      param.Field[SessionChatParamsPartsType] `json:"type,required"`
+	Filename  param.Field[string]                     `json:"filename"`
+	Mime      param.Field[string]                     `json:"mime"`
+	Synthetic param.Field[bool]                       `json:"synthetic"`
+	Text      param.Field[string]                     `json:"text"`
+	Time      param.Field[interface{}]                `json:"time"`
+	URL       param.Field[string]                     `json:"url"`
 }
 
-func init() {
-	apijson.RegisterUnion(
-		reflect.TypeOf((*UserMessagePartUnion)(nil)).Elem(),
-		"type",
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(TextPart{}),
-			DiscriminatorValue: "text",
-		},
-		apijson.UnionVariant{
-			TypeFilter:         gjson.JSON,
-			Type:               reflect.TypeOf(FilePart{}),
-			DiscriminatorValue: "file",
-		},
-	)
+func (r SessionChatParamsPart) MarshalJSON() (data []byte, err error) {
+	return apijson.MarshalRoot(r)
 }
 
-type UserMessagePartType string
+func (r SessionChatParamsPart) implementsSessionChatParamsPartUnion() {}
+
+// Satisfied by [FilePartParam], [TextPartParam], [SessionChatParamsPart].
+type SessionChatParamsPartUnion interface {
+	implementsSessionChatParamsPartUnion()
+}
+
+type SessionChatParamsPartsType string
 
 const (
-	UserMessagePartTypeText UserMessagePartType = "text"
-	UserMessagePartTypeFile UserMessagePartType = "file"
+	SessionChatParamsPartsTypeFile SessionChatParamsPartsType = "file"
+	SessionChatParamsPartsTypeText SessionChatParamsPartsType = "text"
 )
 
-func (r UserMessagePartType) IsKnown() bool {
+func (r SessionChatParamsPartsType) IsKnown() bool {
 	switch r {
-	case UserMessagePartTypeText, UserMessagePartTypeFile:
+	case SessionChatParamsPartsTypeFile, SessionChatParamsPartsTypeText:
 		return true
 	}
 	return false
 }
 
-type UserMessagePartParam struct {
-	Type      param.Field[UserMessagePartType] `json:"type,required"`
-	Filename  param.Field[string]              `json:"filename"`
-	Mime      param.Field[string]              `json:"mime"`
-	Synthetic param.Field[bool]                `json:"synthetic"`
-	Text      param.Field[string]              `json:"text"`
-	URL       param.Field[string]              `json:"url"`
-}
-
-func (r UserMessagePartParam) MarshalJSON() (data []byte, err error) {
-	return apijson.MarshalRoot(r)
-}
-
-func (r UserMessagePartParam) implementsUserMessagePartUnionParam() {}
-
-// Satisfied by [TextPartParam], [FilePartParam], [UserMessagePartParam].
-type UserMessagePartUnionParam interface {
-	implementsUserMessagePartUnionParam()
-}
-
-type SessionChatParams struct {
-	Mode       param.Field[string]                      `json:"mode,required"`
-	ModelID    param.Field[string]                      `json:"modelID,required"`
-	Parts      param.Field[[]UserMessagePartUnionParam] `json:"parts,required"`
-	ProviderID param.Field[string]                      `json:"providerID,required"`
-}
-
-func (r SessionChatParams) MarshalJSON() (data []byte, err error) {
-	return apijson.MarshalRoot(r)
-}
-
 type SessionInitParams struct {
+	MessageID  param.Field[string] `json:"messageID,required"`
 	ModelID    param.Field[string] `json:"modelID,required"`
 	ProviderID param.Field[string] `json:"providerID,required"`
 }
diff --git a/packages/tui/sdk/session_test.go b/packages/tui/sdk/session_test.go
index 4ff2818c5..c74a4a385 100644
--- a/packages/tui/sdk/session_test.go
+++ b/packages/tui/sdk/session_test.go
@@ -117,12 +117,17 @@ func TestSessionChat(t *testing.T) {
 		context.TODO(),
 		"id",
 		opencode.SessionChatParams{
-			Mode:    opencode.F("mode"),
-			ModelID: opencode.F("modelID"),
-			Parts: opencode.F([]opencode.UserMessagePartUnionParam{opencode.TextPartParam{
-				Text:      opencode.F("text"),
-				Type:      opencode.F(opencode.TextPartTypeText),
-				Synthetic: opencode.F(true),
+			MessageID: opencode.F("messageID"),
+			Mode:      opencode.F("mode"),
+			ModelID:   opencode.F("modelID"),
+			Parts: opencode.F([]opencode.SessionChatParamsPartUnion{opencode.FilePartParam{
+				ID:        opencode.F("id"),
+				MessageID: opencode.F("messageID"),
+				Mime:      opencode.F("mime"),
+				SessionID: opencode.F("sessionID"),
+				Type:      opencode.F(opencode.FilePartTypeFile),
+				URL:       opencode.F("url"),
+				Filename:  opencode.F("filename"),
 			}}),
 			ProviderID: opencode.F("providerID"),
 		},
@@ -152,6 +157,7 @@ func TestSessionInit(t *testing.T) {
 		context.TODO(),
 		"id",
 		opencode.SessionInitParams{
+			MessageID:  opencode.F("messageID"),
 			ModelID:    opencode.F("modelID"),
 			ProviderID: opencode.F("providerID"),
 		},
diff --git a/packages/tui/sdk/usage_test.go b/packages/tui/sdk/usage_test.go
index 0e261a7aa..5e8f44c7c 100644
--- a/packages/tui/sdk/usage_test.go
+++ b/packages/tui/sdk/usage_test.go
@@ -23,10 +23,13 @@ func TestUsage(t *testing.T) {
 	client := opencode.NewClient(
 		option.WithBaseURL(baseURL),
 	)
-	events, err := client.Event.List(context.TODO())
+	stream := client.Event.ListStreaming(context.TODO())
+	for stream.Next() {
+		t.Logf("%+v\n", stream.Current())
+	}
+	err := stream.Err()
 	if err != nil {
 		t.Error(err)
 		return
 	}
-	t.Logf("%+v\n", events)
 }