From 408d4f9cc33d59cb1ec52d509ff701b5d28e5178 Mon Sep 17 00:00:00 2001
From: sechmachine <97589681+sechmachine727@users.noreply.github.com>
Date: Mon, 10 Aug 2026 23:07:04 +0700
Subject: [PATCH] feat(protocol): negotiate display and native input

---
 .../conformance/gateway-input-feedback-v1.tsv |   7 +
 fixtures/conformance/tunnel-v1.tsv            |   3 +
 fixtures/manifest.json                        |   2 +-
 frames/gateway-input-feedback-v1.md           |  22 ++-
 gen/go/protocol/protocol.go                   | 166 +++++++++++++++---
 gen/manifest.json                             |   4 +-
 gen/rust/protocol.rs                          |  61 ++++++-
 gen/swift/Protocol.swift                      |  75 +++++++-
 .../.openspec.yaml                            |   2 +
 .../phase-3d-client-display-input/design.md   |  54 ++++++
 .../phase-3d-client-display-input/proposal.md |  38 ++++
 .../specs/gateway-input-feedback/spec.md      |  33 ++++
 .../specs/session-display-mode/spec.md        |  35 ++++
 .../phase-3d-client-display-input/tasks.md    |  17 ++
 registries/features.json                      |   5 +-
 schemas/control-v1.schema.json                |  20 ++-
 tests/go/protocol_test.go                     |  78 ++++++++
 tools/generate.py                             |  18 +-
 tools/go-conformance/main.go                  |  19 +-
 tools/native_conformance.rs                   |  14 +-
 tools/native_conformance.swift                |  13 +-
 tools/test_generated_contracts.py             |  56 ++++++
 tools/validate.py                             |  18 ++
 tools/validate_gateway_envelopes.py           |   7 +
 24 files changed, 707 insertions(+), 60 deletions(-)
 create mode 100644 openspec/changes/phase-3d-client-display-input/.openspec.yaml
 create mode 100644 openspec/changes/phase-3d-client-display-input/design.md
 create mode 100644 openspec/changes/phase-3d-client-display-input/proposal.md
 create mode 100644 openspec/changes/phase-3d-client-display-input/specs/gateway-input-feedback/spec.md
 create mode 100644 openspec/changes/phase-3d-client-display-input/specs/session-display-mode/spec.md
 create mode 100644 openspec/changes/phase-3d-client-display-input/tasks.md

diff --git a/fixtures/conformance/gateway-input-feedback-v1.tsv b/fixtures/conformance/gateway-input-feedback-v1.tsv
index 8389d74..686f5ac 100644
--- a/fixtures/conformance/gateway-input-feedback-v1.tsv
+++ b/fixtures/conformance/gateway-input-feedback-v1.tsv
@@ -7,6 +7,8 @@ valid-relative-mouse	1	gateway_input	hex=564749310304fffe0003	valid
 valid-utf8-scalar	1	gateway_input	hex=564749310403e29883	valid
 valid-controller	1	gateway_input	hex=5647493105110200030004ffff00010002000300040005	valid
 valid-controller-release	1	gateway_input	hex=5647493105110200000000000000000000000000000000	valid
+valid-absolute-mouse	1	gateway_input	hex=56474931060804d202370a0005a0	valid
+valid-scroll	1	gateway_input	hex=564749310704ff880078	valid
 valid-idr	1	gateway_feedback	hex=5647463100010000	valid
 valid-fec	1	gateway_feedback	hex=56474631000200150000002a000500030002000a000200080002140001	valid
 valid-terminal-receipt	1	gateway_feedback	hex=5647463100030000	valid
@@ -18,6 +20,11 @@ invalid-input-kind	1	gateway_input	hex=564749317f00	invalid:kind
 invalid-input-reserved	1	gateway_input	hex=564749310203010101	invalid:reserved
 invalid-input-utf8	1	gateway_input	hex=564749310402c328	invalid:utf8
 invalid-input-length	1	gateway_input	hex=564749310104010200	invalid:length
+invalid-absolute-zero-viewport	1	gateway_input	hex=56474931060800000000000005a0	invalid:field
+invalid-absolute-x-out-of-range	1	gateway_input	hex=5647493106080a0000000a0005a0	invalid:field
+invalid-absolute-y-out-of-range	1	gateway_input	hex=564749310608000005a00a0005a0	invalid:field
+invalid-absolute-length	1	gateway_input	hex=56474931060700000000010001	invalid:length
+invalid-scroll-length	1	gateway_input	hex=5647493107020000	invalid:length
 invalid-feedback-direction	1	gateway_feedback	hex=5647463101020000	invalid:direction
 invalid-terminal-receipt-direction	1	gateway_feedback	hex=5647463101030000	invalid:direction
 invalid-terminal-receipt-body	1	gateway_feedback	hex=5647463100030001ff	invalid:length
diff --git a/fixtures/conformance/tunnel-v1.tsv b/fixtures/conformance/tunnel-v1.tsv
index c4cd4cb..dfbbc31 100644
--- a/fixtures/conformance/tunnel-v1.tsv
+++ b/fixtures/conformance/tunnel-v1.tsv
@@ -2,5 +2,8 @@ id	version	kind	input	expected
 tunnel-current	1	tunnel	offered=1;feature=control.v1	valid
 tunnel-n-minus-1	0	tunnel	offered=0;feature=control.v1	valid
 tunnel-n-minus-2	-1	tunnel	offered=-1;feature=control.v1	valid
+tunnel-display-request	1	tunnel	offered=1;feature=display.request.v1	valid
+tunnel-absolute-input	1	tunnel	offered=1;feature=input.absolute.v1	valid
+tunnel-scroll-input	1	tunnel	offered=1;feature=input.scroll.v1	valid
 tunnel-unsupported	1	tunnel	offered=2;feature=control.v1	invalid:unsupported_version
 tunnel-no-control	1	tunnel	offered=1;feature=media.video	invalid:unsupported_feature
diff --git a/fixtures/manifest.json b/fixtures/manifest.json
index 9b2dabe..74aa16f 100644
--- a/fixtures/manifest.json
+++ b/fixtures/manifest.json
@@ -10,5 +10,5 @@
     "fixtures/conformance/gateway-input-feedback-v1.tsv",
     "fixtures/conformance/tunnel-v1.tsv"
   ],
-  "corpus_sha256": "544ba8765b4ddcfbe807d1d6e6788fe03d06b8e50d1424b82e4e512312e51248"
+  "corpus_sha256": "4f8bf520d4f61588235b00776b21202ff701b20d6d11b461037b911c2117852b"
 }
diff --git a/frames/gateway-input-feedback-v1.md b/frames/gateway-input-feedback-v1.md
index 838d561..d50903f 100644
--- a/frames/gateway-input-feedback-v1.md
+++ b/frames/gateway-input-feedback-v1.md
@@ -4,12 +4,14 @@ This grammar is carried only in an authenticated Phase 3C gateway session. It
 is deliberately provider-neutral: it never carries provider routes,
 certificates, credentials, opaque provider packets, clipboard bytes, files, or
 client-folder data. It does not change the v1 datagram header or any existing
-release candidate.
+kind encoding; the new kinds require explicit feature negotiation and a new
+immutable Protocol release candidate.
 
 ## `input.sequenced.v1` payload (`VGI1`)
 
-All multibyte fields are unsigned big-endian. The payload has exactly six bytes
-of header followed by the declared body:
+All multibyte fields are big-endian and unsigned unless a field is explicitly
+marked signed. The payload has exactly six bytes of header followed by the
+declared body:
 
 | Offset | Size | Field | Rule |
 |---:|---:|---|---|
@@ -32,12 +34,16 @@ during cleanup.
 | `0x03` | relative mouse | `delta_x` (i16), `delta_y` (i16). |
 | `0x04` | UTF-8 scalar | exactly one valid UTF-8 Unicode scalar, one through four bytes. |
 | `0x05` | controller state | `controller` (0 through 15), `active_mask` (u16), `button_flags` (u16), `left_trigger` (u8), `right_trigger` (u8), `left_x` (i16), `left_y` (i16), `right_x` (i16), `right_y` (i16), `extra_button_flags` (u16). A zero `active_mask` and zero state is release. |
+| `0x06` | absolute mouse | `x` (u16), `y` (u16), `viewport_width` (u16), `viewport_height` (u16). Viewport dimensions must be nonzero and each coordinate must be strictly smaller than its corresponding dimension. |
+| `0x07` | high-resolution scroll | `vertical_delta` (i16), `horizontal_delta` (i16). Positive and negative values preserve the client scroll direction without provider-specific scaling. |
 
-Keyboard, mouse button, UTF-8, and controller messages are delivered over the
-gateway's reliable ordered input flow. Relative mouse is a state change, not a
-pressed-state entry. The gateway maps the validated values to the provider's
-separate keyboard, mouse, UTF-8, and controller control messages; it does not
-forward this envelope to the provider.
+Keyboard, mouse button, UTF-8, controller, absolute mouse, and scroll messages
+are delivered over the gateway's reliable ordered input flow. Relative and
+absolute mouse movement and scroll are state changes, not pressed-state
+entries. Kinds `0x06` and `0x07` are accepted only when the session advertises
+`input.absolute.v1` and `input.scroll.v1`, respectively. The gateway maps the
+validated values to the provider's separate input messages; it does not forward
+this envelope to the provider.
 
 ## Reliable control payload (`VGF1`)
 
diff --git a/gen/go/protocol/protocol.go b/gen/go/protocol/protocol.go
index 238b2f1..5c0a34c 100644
--- a/gen/go/protocol/protocol.go
+++ b/gen/go/protocol/protocol.go
@@ -13,7 +13,7 @@ import (
 	"time"
 )
 
-const SchemaSHA256 = "a86cbdaf2cfb884e3d98467968007e731ca55c6f6eb6dbd5cd6b95e062a9b058"
+const SchemaSHA256 = "b2bb0a8ac8ef56dbc0e1443eeb5b3028be9e71ec2f5fd8e73928d71b7cd9340c"
 const ProtocolVersion = "1.0.0"
 const CurrentWireVersion = "1"
 const NMinus1WireVersion = "0"
@@ -50,21 +50,23 @@ type AssignedDesktop struct {
 }
 
 type BrokerSession struct {
-	ID                string           `json:"id"`
-	PrincipalID       string           `json:"principal_id"`
-	PoolID            string           `json:"pool_id"`
-	AssignmentID      string           `json:"assignment_id,omitempty"`
-	State             string           `json:"state"`
-	PolicySnapshot    AllocationPolicy `json:"policy_snapshot"`
-	ReconnectDeadline string           `json:"reconnect_deadline,omitempty"`
-	Outcome           string           `json:"outcome,omitempty"`
-	FailureCode       string           `json:"failure_code,omitempty"`
-	CleanupState      string           `json:"cleanup_state"`
-	IdempotencyKey    string           `json:"idempotency_key"`
-	CorrelationID     string           `json:"correlation_id"`
-	RequestedAt       string           `json:"requested_at"`
-	EndedAt           string           `json:"ended_at,omitempty"`
-	Version           int64            `json:"version"`
+	ID                   string           `json:"id"`
+	PrincipalID          string           `json:"principal_id"`
+	PoolID               string           `json:"pool_id"`
+	AssignmentID         string           `json:"assignment_id,omitempty"`
+	State                string           `json:"state"`
+	PolicySnapshot       AllocationPolicy `json:"policy_snapshot"`
+	ReconnectDeadline    string           `json:"reconnect_deadline,omitempty"`
+	Outcome              string           `json:"outcome,omitempty"`
+	FailureCode          string           `json:"failure_code,omitempty"`
+	CleanupState         string           `json:"cleanup_state"`
+	IdempotencyKey       string           `json:"idempotency_key"`
+	CorrelationID        string           `json:"correlation_id"`
+	RequestedAt          string           `json:"requested_at"`
+	EndedAt              string           `json:"ended_at,omitempty"`
+	Version              int64            `json:"version"`
+	RequestedDisplayMode *DisplayMode     `json:"requested_display_mode,omitempty"`
+	EffectiveDisplayMode *DisplayMode     `json:"effective_display_mode,omitempty"`
 }
 
 type CapabilityProfile struct {
@@ -134,6 +136,12 @@ type DeviceRegistrationRequest struct {
 	PublicKey     string `json:"public_key"`
 }
 
+type DisplayMode struct {
+	ResolutionWidth  int64 `json:"resolution_width"`
+	ResolutionHeight int64 `json:"resolution_height"`
+	Fps              int64 `json:"fps"`
+}
+
 type EntitledPool struct {
 	PoolID          string `json:"pool_id"`
 	Name            string `json:"name"`
@@ -263,8 +271,9 @@ type ManifestGateway struct {
 }
 
 type ManifestProfile struct {
-	ID     string         `json:"id"`
-	Bounds ManifestBounds `json:"bounds"`
+	ID          string         `json:"id"`
+	Bounds      ManifestBounds `json:"bounds"`
+	DisplayMode *DisplayMode   `json:"display_mode,omitempty"`
 }
 
 type ManifestTunnel struct {
@@ -383,11 +392,12 @@ type SessionAuthority struct {
 }
 
 type SessionRequest struct {
-	ClientDeviceID string           `json:"client_device_id"`
-	DeviceKeyID    string           `json:"device_key_id"`
-	PoolID         string           `json:"pool_id"`
-	IdempotencyKey string           `json:"idempotency_key"`
-	PolicySnapshot AllocationPolicy `json:"policy_snapshot"`
+	ClientDeviceID       string           `json:"client_device_id"`
+	DeviceKeyID          string           `json:"device_key_id"`
+	PoolID               string           `json:"pool_id"`
+	IdempotencyKey       string           `json:"idempotency_key"`
+	PolicySnapshot       AllocationPolicy `json:"policy_snapshot"`
+	RequestedDisplayMode *DisplayMode     `json:"requested_display_mode,omitempty"`
 }
 
 type StableError struct {
@@ -767,6 +777,16 @@ func (v BrokerSession) Validate() error {
 	if v.Version != 0 && v.Version < 1 {
 		violations = append(violations, FieldViolation{Field: "version", Code: "minimum"})
 	}
+	if v.RequestedDisplayMode != nil {
+		if err := v.RequestedDisplayMode.Validate(); err != nil {
+			violations = append(violations, FieldViolation{Field: "requested_display_mode", Code: "invalid_object"})
+		}
+	}
+	if v.EffectiveDisplayMode != nil {
+		if err := v.EffectiveDisplayMode.Validate(); err != nil {
+			violations = append(violations, FieldViolation{Field: "effective_display_mode", Code: "invalid_object"})
+		}
+	}
 	if len(violations) > 0 {
 		return ValidationError{Violations: violations}
 	}
@@ -812,6 +832,12 @@ func DecodeBrokerSession(data []byte) (BrokerSession, error) {
 	if raw, ok := fields["version"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
 		return value, ValidationError{Violations: []FieldViolation{{Field: "version", Code: "required"}}}
 	}
+	if raw, ok := fields["requested_display_mode"]; ok && bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "requested_display_mode", Code: "invalid_object"}}}
+	}
+	if raw, ok := fields["effective_display_mode"]; ok && bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "effective_display_mode", Code: "invalid_object"}}}
+	}
 	decoder := json.NewDecoder(bytes.NewReader(data))
 	decoder.DisallowUnknownFields()
 	if err := decoder.Decode(&value); err != nil {
@@ -1625,6 +1651,84 @@ func EncodeDeviceRegistrationRequest(value DeviceRegistrationRequest) ([]byte, e
 	return json.Marshal(value)
 }
 
+func (v DisplayMode) Validate() error {
+	var violations []FieldViolation
+	if v.ResolutionWidth == 0 {
+		violations = append(violations, FieldViolation{Field: "resolution_width", Code: "required"})
+	}
+	if v.ResolutionWidth != 0 && v.ResolutionWidth < 320 {
+		violations = append(violations, FieldViolation{Field: "resolution_width", Code: "minimum"})
+	}
+	if v.ResolutionWidth > 16384 {
+		violations = append(violations, FieldViolation{Field: "resolution_width", Code: "maximum"})
+	}
+	if v.ResolutionHeight == 0 {
+		violations = append(violations, FieldViolation{Field: "resolution_height", Code: "required"})
+	}
+	if v.ResolutionHeight != 0 && v.ResolutionHeight < 200 {
+		violations = append(violations, FieldViolation{Field: "resolution_height", Code: "minimum"})
+	}
+	if v.ResolutionHeight > 8640 {
+		violations = append(violations, FieldViolation{Field: "resolution_height", Code: "maximum"})
+	}
+	if v.Fps == 0 {
+		violations = append(violations, FieldViolation{Field: "fps", Code: "required"})
+	}
+	if v.Fps != 0 && v.Fps < 1 {
+		violations = append(violations, FieldViolation{Field: "fps", Code: "minimum"})
+	}
+	if v.Fps > 240 {
+		violations = append(violations, FieldViolation{Field: "fps", Code: "maximum"})
+	}
+	if len(violations) > 0 {
+		return ValidationError{Violations: violations}
+	}
+	return nil
+}
+
+func DecodeDisplayMode(data []byte) (DisplayMode, error) {
+	var value DisplayMode
+	if len(data) > 1024*1024 {
+		return value, errors.New("protocol payload exceeds limit")
+	}
+	var fields map[string]json.RawMessage
+	if err := json.Unmarshal(data, &fields); err != nil {
+		return value, err
+	}
+	if raw, ok := fields["fps"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "fps", Code: "required"}}}
+	}
+	if raw, ok := fields["resolution_height"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "resolution_height", Code: "required"}}}
+	}
+	if raw, ok := fields["resolution_width"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "resolution_width", Code: "required"}}}
+	}
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.DisallowUnknownFields()
+	if err := decoder.Decode(&value); err != nil {
+		return value, err
+	}
+	var trailing any
+	if err := decoder.Decode(&trailing); err != io.EOF {
+		if err == nil {
+			return value, errors.New("trailing JSON value")
+		}
+		return value, err
+	}
+	if err := value.Validate(); err != nil {
+		return value, err
+	}
+	return value, nil
+}
+
+func EncodeDisplayMode(value DisplayMode) ([]byte, error) {
+	if err := value.Validate(); err != nil {
+		return nil, err
+	}
+	return json.Marshal(value)
+}
+
 func (v EntitledPool) Validate() error {
 	var violations []FieldViolation
 	if v.PoolID == "" {
@@ -3202,6 +3306,11 @@ func (v ManifestProfile) Validate() error {
 	if err := v.Bounds.Validate(); err != nil {
 		violations = append(violations, FieldViolation{Field: "bounds", Code: "invalid_object"})
 	}
+	if v.DisplayMode != nil {
+		if err := v.DisplayMode.Validate(); err != nil {
+			violations = append(violations, FieldViolation{Field: "display_mode", Code: "invalid_object"})
+		}
+	}
 	if len(violations) > 0 {
 		return ValidationError{Violations: violations}
 	}
@@ -3223,6 +3332,9 @@ func DecodeManifestProfile(data []byte) (ManifestProfile, error) {
 	if raw, ok := fields["id"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
 		return value, ValidationError{Violations: []FieldViolation{{Field: "id", Code: "required"}}}
 	}
+	if raw, ok := fields["display_mode"]; ok && bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "display_mode", Code: "invalid_object"}}}
+	}
 	decoder := json.NewDecoder(bytes.NewReader(data))
 	decoder.DisallowUnknownFields()
 	if err := decoder.Decode(&value); err != nil {
@@ -4655,6 +4767,11 @@ func (v SessionRequest) Validate() error {
 	if err := v.PolicySnapshot.Validate(); err != nil {
 		violations = append(violations, FieldViolation{Field: "policy_snapshot", Code: "invalid_object"})
 	}
+	if v.RequestedDisplayMode != nil {
+		if err := v.RequestedDisplayMode.Validate(); err != nil {
+			violations = append(violations, FieldViolation{Field: "requested_display_mode", Code: "invalid_object"})
+		}
+	}
 	if len(violations) > 0 {
 		return ValidationError{Violations: violations}
 	}
@@ -4685,6 +4802,9 @@ func DecodeSessionRequest(data []byte) (SessionRequest, error) {
 	if raw, ok := fields["pool_id"]; !ok || bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
 		return value, ValidationError{Violations: []FieldViolation{{Field: "pool_id", Code: "required"}}}
 	}
+	if raw, ok := fields["requested_display_mode"]; ok && bytes.Equal(bytes.TrimSpace(raw), []byte("null")) {
+		return value, ValidationError{Violations: []FieldViolation{{Field: "requested_display_mode", Code: "invalid_object"}}}
+	}
 	decoder := json.NewDecoder(bytes.NewReader(data))
 	decoder.DisallowUnknownFields()
 	if err := decoder.Decode(&value); err != nil {
diff --git a/gen/manifest.json b/gen/manifest.json
index 8476f14..b7ead5c 100644
--- a/gen/manifest.json
+++ b/gen/manifest.json
@@ -12,7 +12,7 @@
       "2"
     ]
   },
-  "generator_sha256": "00fdba050eb924a54dd3d63aac0a38560341b675f0de4e3e9631ee895057a9b6",
+  "generator_sha256": "992235a56d3467313148f86e47931f247591e4c8de737b55ac9c9eee35725fc5",
   "protocol_version": "1.0.0",
-  "schema_sha256": "a86cbdaf2cfb884e3d98467968007e731ca55c6f6eb6dbd5cd6b95e062a9b058"
+  "schema_sha256": "b2bb0a8ac8ef56dbc0e1443eeb5b3028be9e71ec2f5fd8e73928d71b7cd9340c"
 }
diff --git a/gen/rust/protocol.rs b/gen/rust/protocol.rs
index d8377b3..1b623c3 100644
--- a/gen/rust/protocol.rs
+++ b/gen/rust/protocol.rs
@@ -1,6 +1,6 @@
 // Code generated by tools/generate.py; DO NOT EDIT.
 #![allow(non_snake_case)]
-pub const SCHEMA_SHA256: &str = "a86cbdaf2cfb884e3d98467968007e731ca55c6f6eb6dbd5cd6b95e062a9b058";
+pub const SCHEMA_SHA256: &str = "b2bb0a8ac8ef56dbc0e1443eeb5b3028be9e71ec2f5fd8e73928d71b7cd9340c";
 pub const CURRENT_WIRE_VERSION: &str = "1";
 pub const N_MINUS_1_WIRE_VERSION: &str = "0";
 pub const N_MINUS_2_WIRE_VERSION: &str = "-1";
@@ -136,11 +136,13 @@ pub struct BrokerSession {
     requestedAt: String,
     endedAt: Option<String>,
     version: i64,
+    requestedDisplayMode: Option<DisplayMode>,
+    effectiveDisplayMode: Option<DisplayMode>,
 }
 
 impl BrokerSession {
-    pub fn new(id: String, principalId: String, poolId: String, assignmentId: Option<String>, state: String, policySnapshot: AllocationPolicy, reconnectDeadline: Option<String>, outcome: Option<String>, failureCode: Option<String>, cleanupState: String, idempotencyKey: String, correlationId: String, requestedAt: String, endedAt: Option<String>, version: i64) -> Result<Self, ValidationError> {
-        let value = Self { id, principalId, poolId, assignmentId, state, policySnapshot, reconnectDeadline, outcome, failureCode, cleanupState, idempotencyKey, correlationId, requestedAt, endedAt, version };
+    pub fn new(id: String, principalId: String, poolId: String, assignmentId: Option<String>, state: String, policySnapshot: AllocationPolicy, reconnectDeadline: Option<String>, outcome: Option<String>, failureCode: Option<String>, cleanupState: String, idempotencyKey: String, correlationId: String, requestedAt: String, endedAt: Option<String>, version: i64, requestedDisplayMode: Option<DisplayMode>, effectiveDisplayMode: Option<DisplayMode>) -> Result<Self, ValidationError> {
+        let value = Self { id, principalId, poolId, assignmentId, state, policySnapshot, reconnectDeadline, outcome, failureCode, cleanupState, idempotencyKey, correlationId, requestedAt, endedAt, version, requestedDisplayMode, effectiveDisplayMode };
         value.validate()?;
         Ok(value)
     }
@@ -184,6 +186,12 @@ impl BrokerSession {
             if value.len() > 64 { return Err(ValidationError::new("ended_at", "max_length")); }
         }
         if self.version < 1 { return Err(ValidationError::new("version", "minimum")); }
+        if let Some(value) = &self.requestedDisplayMode {
+            value.validate().map_err(|_| ValidationError::new("requested_display_mode", "invalid_object"))?;
+        }
+        if let Some(value) = &self.effectiveDisplayMode {
+            value.validate().map_err(|_| ValidationError::new("effective_display_mode", "invalid_object"))?;
+        }
         Ok(())
     }
     pub fn id(&self) -> &String { &self.id }
@@ -201,6 +209,8 @@ impl BrokerSession {
     pub fn requestedAt(&self) -> &String { &self.requestedAt }
     pub fn endedAt(&self) -> &Option<String> { &self.endedAt }
     pub fn version(&self) -> &i64 { &self.version }
+    pub fn requestedDisplayMode(&self) -> &Option<DisplayMode> { &self.requestedDisplayMode }
+    pub fn effectiveDisplayMode(&self) -> &Option<DisplayMode> { &self.effectiveDisplayMode }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -494,6 +504,33 @@ impl DeviceRegistrationRequest {
     pub fn publicKey(&self) -> &String { &self.publicKey }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct DisplayMode {
+    resolutionWidth: i64,
+    resolutionHeight: i64,
+    fps: i64,
+}
+
+impl DisplayMode {
+    pub fn new(resolutionWidth: i64, resolutionHeight: i64, fps: i64) -> Result<Self, ValidationError> {
+        let value = Self { resolutionWidth, resolutionHeight, fps };
+        value.validate()?;
+        Ok(value)
+    }
+    pub fn validate(&self) -> Result<(), ValidationError> {
+        if self.resolutionWidth < 320 { return Err(ValidationError::new("resolution_width", "minimum")); }
+        if self.resolutionWidth > 16384 { return Err(ValidationError::new("resolution_width", "maximum")); }
+        if self.resolutionHeight < 200 { return Err(ValidationError::new("resolution_height", "minimum")); }
+        if self.resolutionHeight > 8640 { return Err(ValidationError::new("resolution_height", "maximum")); }
+        if self.fps < 1 { return Err(ValidationError::new("fps", "minimum")); }
+        if self.fps > 240 { return Err(ValidationError::new("fps", "maximum")); }
+        Ok(())
+    }
+    pub fn resolutionWidth(&self) -> &i64 { &self.resolutionWidth }
+    pub fn resolutionHeight(&self) -> &i64 { &self.resolutionHeight }
+    pub fn fps(&self) -> &i64 { &self.fps }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct EntitledPool {
     poolId: String,
@@ -1080,11 +1117,12 @@ impl ManifestGateway {
 pub struct ManifestProfile {
     id: String,
     bounds: ManifestBounds,
+    displayMode: Option<DisplayMode>,
 }
 
 impl ManifestProfile {
-    pub fn new(id: String, bounds: ManifestBounds) -> Result<Self, ValidationError> {
-        let value = Self { id, bounds };
+    pub fn new(id: String, bounds: ManifestBounds, displayMode: Option<DisplayMode>) -> Result<Self, ValidationError> {
+        let value = Self { id, bounds, displayMode };
         value.validate()?;
         Ok(value)
     }
@@ -1093,10 +1131,14 @@ impl ManifestProfile {
         if !self.id.is_empty() && self.id.len() < 1 { return Err(ValidationError::new("id", "min_length")); }
         if self.id.len() > 128 { return Err(ValidationError::new("id", "max_length")); }
         self.bounds.validate().map_err(|_| ValidationError::new("bounds", "invalid_object"))?;
+        if let Some(value) = &self.displayMode {
+            value.validate().map_err(|_| ValidationError::new("display_mode", "invalid_object"))?;
+        }
         Ok(())
     }
     pub fn id(&self) -> &String { &self.id }
     pub fn bounds(&self) -> &ManifestBounds { &self.bounds }
+    pub fn displayMode(&self) -> &Option<DisplayMode> { &self.displayMode }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -1613,11 +1655,12 @@ pub struct SessionRequest {
     poolId: String,
     idempotencyKey: String,
     policySnapshot: AllocationPolicy,
+    requestedDisplayMode: Option<DisplayMode>,
 }
 
 impl SessionRequest {
-    pub fn new(clientDeviceId: String, deviceKeyId: String, poolId: String, idempotencyKey: String, policySnapshot: AllocationPolicy) -> Result<Self, ValidationError> {
-        let value = Self { clientDeviceId, deviceKeyId, poolId, idempotencyKey, policySnapshot };
+    pub fn new(clientDeviceId: String, deviceKeyId: String, poolId: String, idempotencyKey: String, policySnapshot: AllocationPolicy, requestedDisplayMode: Option<DisplayMode>) -> Result<Self, ValidationError> {
+        let value = Self { clientDeviceId, deviceKeyId, poolId, idempotencyKey, policySnapshot, requestedDisplayMode };
         value.validate()?;
         Ok(value)
     }
@@ -1635,6 +1678,9 @@ impl SessionRequest {
         if !self.idempotencyKey.is_empty() && self.idempotencyKey.len() < 1 { return Err(ValidationError::new("idempotency_key", "min_length")); }
         if self.idempotencyKey.len() > 256 { return Err(ValidationError::new("idempotency_key", "max_length")); }
         self.policySnapshot.validate().map_err(|_| ValidationError::new("policy_snapshot", "invalid_object"))?;
+        if let Some(value) = &self.requestedDisplayMode {
+            value.validate().map_err(|_| ValidationError::new("requested_display_mode", "invalid_object"))?;
+        }
         Ok(())
     }
     pub fn clientDeviceId(&self) -> &String { &self.clientDeviceId }
@@ -1642,6 +1688,7 @@ impl SessionRequest {
     pub fn poolId(&self) -> &String { &self.poolId }
     pub fn idempotencyKey(&self) -> &String { &self.idempotencyKey }
     pub fn policySnapshot(&self) -> &AllocationPolicy { &self.policySnapshot }
+    pub fn requestedDisplayMode(&self) -> &Option<DisplayMode> { &self.requestedDisplayMode }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
diff --git a/gen/swift/Protocol.swift b/gen/swift/Protocol.swift
index 01a7bc0..700171d 100644
--- a/gen/swift/Protocol.swift
+++ b/gen/swift/Protocol.swift
@@ -1,7 +1,7 @@
 // Code generated by tools/generate.py; DO NOT EDIT.
 import Foundation
 public typealias JSONObject = [String: String]
-public let schemaSHA256 = "a86cbdaf2cfb884e3d98467968007e731ca55c6f6eb6dbd5cd6b95e062a9b058"
+public let schemaSHA256 = "b2bb0a8ac8ef56dbc0e1443eeb5b3028be9e71ec2f5fd8e73928d71b7cd9340c"
 public let currentWireVersion = "1"
 public let nMinus1WireVersion = "0"
 public let nMinus2WireVersion = "-1"
@@ -148,6 +148,8 @@ public struct BrokerSession: Codable, Equatable {
     public let requestedAt: String
     public let endedAt: String?
     public let version: Int64
+    public let requestedDisplayMode: DisplayMode?
+    public let effectiveDisplayMode: DisplayMode?
     enum CodingKeys: String, CodingKey {
         case id = "id"
         case principalId = "principal_id"
@@ -164,9 +166,11 @@ public struct BrokerSession: Codable, Equatable {
         case requestedAt = "requested_at"
         case endedAt = "ended_at"
         case version = "version"
+        case requestedDisplayMode = "requested_display_mode"
+        case effectiveDisplayMode = "effective_display_mode"
     }
 
-    public init(id: String, principalId: String, poolId: String, assignmentId: String?, state: String, policySnapshot: AllocationPolicy, reconnectDeadline: String?, outcome: String?, failureCode: String?, cleanupState: String, idempotencyKey: String, correlationId: String, requestedAt: String, endedAt: String?, version: Int64) throws {
+    public init(id: String, principalId: String, poolId: String, assignmentId: String?, state: String, policySnapshot: AllocationPolicy, reconnectDeadline: String?, outcome: String?, failureCode: String?, cleanupState: String, idempotencyKey: String, correlationId: String, requestedAt: String, endedAt: String?, version: Int64, requestedDisplayMode: DisplayMode?, effectiveDisplayMode: DisplayMode?) throws {
         self.id = id
         self.principalId = principalId
         self.poolId = poolId
@@ -182,6 +186,8 @@ public struct BrokerSession: Codable, Equatable {
         self.requestedAt = requestedAt
         self.endedAt = endedAt
         self.version = version
+        self.requestedDisplayMode = requestedDisplayMode
+        self.effectiveDisplayMode = effectiveDisplayMode
         try validate()
     }
 
@@ -189,7 +195,7 @@ public struct BrokerSession: Codable, Equatable {
         let all = try decoder.container(keyedBy: AnyCodingKey.self)
         for key in all.allKeys where CodingKeys(stringValue: key.stringValue) == nil { throw ContractValidationError(field: key.stringValue, code: "unknown_field") }
         let c = try decoder.container(keyedBy: CodingKeys.self)
-        try self.init(id: try c.decode(String.self, forKey: .id), principalId: try c.decode(String.self, forKey: .principalId), poolId: try c.decode(String.self, forKey: .poolId), assignmentId: try c.decodeIfPresent(String.self, forKey: .assignmentId), state: try c.decode(String.self, forKey: .state), policySnapshot: try c.decode(AllocationPolicy.self, forKey: .policySnapshot), reconnectDeadline: try c.decodeIfPresent(String.self, forKey: .reconnectDeadline), outcome: try c.decodeIfPresent(String.self, forKey: .outcome), failureCode: try c.decodeIfPresent(String.self, forKey: .failureCode), cleanupState: try c.decode(String.self, forKey: .cleanupState), idempotencyKey: try c.decode(String.self, forKey: .idempotencyKey), correlationId: try c.decode(String.self, forKey: .correlationId), requestedAt: try c.decode(String.self, forKey: .requestedAt), endedAt: try c.decodeIfPresent(String.self, forKey: .endedAt), version: try c.decode(Int64.self, forKey: .version))
+        try self.init(id: try c.decode(String.self, forKey: .id), principalId: try c.decode(String.self, forKey: .principalId), poolId: try c.decode(String.self, forKey: .poolId), assignmentId: try c.decodeIfPresent(String.self, forKey: .assignmentId), state: try c.decode(String.self, forKey: .state), policySnapshot: try c.decode(AllocationPolicy.self, forKey: .policySnapshot), reconnectDeadline: try c.decodeIfPresent(String.self, forKey: .reconnectDeadline), outcome: try c.decodeIfPresent(String.self, forKey: .outcome), failureCode: try c.decodeIfPresent(String.self, forKey: .failureCode), cleanupState: try c.decode(String.self, forKey: .cleanupState), idempotencyKey: try c.decode(String.self, forKey: .idempotencyKey), correlationId: try c.decode(String.self, forKey: .correlationId), requestedAt: try c.decode(String.self, forKey: .requestedAt), endedAt: try c.decodeIfPresent(String.self, forKey: .endedAt), version: try c.decode(Int64.self, forKey: .version), requestedDisplayMode: try c.contains(.requestedDisplayMode) ? c.decode(DisplayMode.self, forKey: .requestedDisplayMode) : nil, effectiveDisplayMode: try c.contains(.effectiveDisplayMode) ? c.decode(DisplayMode.self, forKey: .effectiveDisplayMode) : nil)
     }
 
     public func validate() throws {
@@ -235,6 +241,12 @@ public struct BrokerSession: Codable, Equatable {
             if ISO8601DateFormatter().date(from: value) == nil { throw ContractValidationError(field: "ended_at", code: "invalid_time") }
         }
         if self.version < 1 { throw ContractValidationError(field: "version", code: "minimum") }
+        if let value = self.requestedDisplayMode {
+            try value.validate()
+        }
+        if let value = self.effectiveDisplayMode {
+            try value.validate()
+        }
     }
 
     public static func decodeJSON(_ data: Data) throws -> Self { try JSONDecoder().decode(Self.self, from: data) }
@@ -632,6 +644,43 @@ public struct DeviceRegistrationRequest: Codable, Equatable {
     public func encodeJSON() throws -> Data { try validate(); return try JSONEncoder().encode(self) }
 }
 
+public struct DisplayMode: Codable, Equatable {
+    public let resolutionWidth: Int64
+    public let resolutionHeight: Int64
+    public let fps: Int64
+    enum CodingKeys: String, CodingKey {
+        case resolutionWidth = "resolution_width"
+        case resolutionHeight = "resolution_height"
+        case fps = "fps"
+    }
+
+    public init(resolutionWidth: Int64, resolutionHeight: Int64, fps: Int64) throws {
+        self.resolutionWidth = resolutionWidth
+        self.resolutionHeight = resolutionHeight
+        self.fps = fps
+        try validate()
+    }
+
+    public init(from decoder: Decoder) throws {
+        let all = try decoder.container(keyedBy: AnyCodingKey.self)
+        for key in all.allKeys where CodingKeys(stringValue: key.stringValue) == nil { throw ContractValidationError(field: key.stringValue, code: "unknown_field") }
+        let c = try decoder.container(keyedBy: CodingKeys.self)
+        try self.init(resolutionWidth: try c.decode(Int64.self, forKey: .resolutionWidth), resolutionHeight: try c.decode(Int64.self, forKey: .resolutionHeight), fps: try c.decode(Int64.self, forKey: .fps))
+    }
+
+    public func validate() throws {
+        if self.resolutionWidth < 320 { throw ContractValidationError(field: "resolution_width", code: "minimum") }
+        if self.resolutionWidth > 16384 { throw ContractValidationError(field: "resolution_width", code: "maximum") }
+        if self.resolutionHeight < 200 { throw ContractValidationError(field: "resolution_height", code: "minimum") }
+        if self.resolutionHeight > 8640 { throw ContractValidationError(field: "resolution_height", code: "maximum") }
+        if self.fps < 1 { throw ContractValidationError(field: "fps", code: "minimum") }
+        if self.fps > 240 { throw ContractValidationError(field: "fps", code: "maximum") }
+    }
+
+    public static func decodeJSON(_ data: Data) throws -> Self { try JSONDecoder().decode(Self.self, from: data) }
+    public func encodeJSON() throws -> Data { try validate(); return try JSONEncoder().encode(self) }
+}
+
 public struct EntitledPool: Codable, Equatable {
     public let poolId: String
     public let name: String
@@ -1414,14 +1463,17 @@ public struct ManifestGateway: Codable, Equatable {
 public struct ManifestProfile: Codable, Equatable {
     public let id: String
     public let bounds: ManifestBounds
+    public let displayMode: DisplayMode?
     enum CodingKeys: String, CodingKey {
         case id = "id"
         case bounds = "bounds"
+        case displayMode = "display_mode"
     }
 
-    public init(id: String, bounds: ManifestBounds) throws {
+    public init(id: String, bounds: ManifestBounds, displayMode: DisplayMode?) throws {
         self.id = id
         self.bounds = bounds
+        self.displayMode = displayMode
         try validate()
     }
 
@@ -1429,7 +1481,7 @@ public struct ManifestProfile: Codable, Equatable {
         let all = try decoder.container(keyedBy: AnyCodingKey.self)
         for key in all.allKeys where CodingKeys(stringValue: key.stringValue) == nil { throw ContractValidationError(field: key.stringValue, code: "unknown_field") }
         let c = try decoder.container(keyedBy: CodingKeys.self)
-        try self.init(id: try c.decode(String.self, forKey: .id), bounds: try c.decode(ManifestBounds.self, forKey: .bounds))
+        try self.init(id: try c.decode(String.self, forKey: .id), bounds: try c.decode(ManifestBounds.self, forKey: .bounds), displayMode: try c.contains(.displayMode) ? c.decode(DisplayMode.self, forKey: .displayMode) : nil)
     }
 
     public func validate() throws {
@@ -1437,6 +1489,9 @@ public struct ManifestProfile: Codable, Equatable {
         if !self.id.isEmpty && self.id.utf8.count < 1 { throw ContractValidationError(field: "id", code: "min_length") }
         if self.id.utf8.count > 128 { throw ContractValidationError(field: "id", code: "max_length") }
         try self.bounds.validate()
+        if let value = self.displayMode {
+            try value.validate()
+        }
     }
 
     public static func decodeJSON(_ data: Data) throws -> Self { try JSONDecoder().decode(Self.self, from: data) }
@@ -2132,20 +2187,23 @@ public struct SessionRequest: Codable, Equatable {
     public let poolId: String
     public let idempotencyKey: String
     public let policySnapshot: AllocationPolicy
+    public let requestedDisplayMode: DisplayMode?
     enum CodingKeys: String, CodingKey {
         case clientDeviceId = "client_device_id"
         case deviceKeyId = "device_key_id"
         case poolId = "pool_id"
         case idempotencyKey = "idempotency_key"
         case policySnapshot = "policy_snapshot"
+        case requestedDisplayMode = "requested_display_mode"
     }
 
-    public init(clientDeviceId: String, deviceKeyId: String, poolId: String, idempotencyKey: String, policySnapshot: AllocationPolicy) throws {
+    public init(clientDeviceId: String, deviceKeyId: String, poolId: String, idempotencyKey: String, policySnapshot: AllocationPolicy, requestedDisplayMode: DisplayMode?) throws {
         self.clientDeviceId = clientDeviceId
         self.deviceKeyId = deviceKeyId
         self.poolId = poolId
         self.idempotencyKey = idempotencyKey
         self.policySnapshot = policySnapshot
+        self.requestedDisplayMode = requestedDisplayMode
         try validate()
     }
 
@@ -2153,7 +2211,7 @@ public struct SessionRequest: Codable, Equatable {
         let all = try decoder.container(keyedBy: AnyCodingKey.self)
         for key in all.allKeys where CodingKeys(stringValue: key.stringValue) == nil { throw ContractValidationError(field: key.stringValue, code: "unknown_field") }
         let c = try decoder.container(keyedBy: CodingKeys.self)
-        try self.init(clientDeviceId: try c.decode(String.self, forKey: .clientDeviceId), deviceKeyId: try c.decode(String.self, forKey: .deviceKeyId), poolId: try c.decode(String.self, forKey: .poolId), idempotencyKey: try c.decode(String.self, forKey: .idempotencyKey), policySnapshot: try c.decode(AllocationPolicy.self, forKey: .policySnapshot))
+        try self.init(clientDeviceId: try c.decode(String.self, forKey: .clientDeviceId), deviceKeyId: try c.decode(String.self, forKey: .deviceKeyId), poolId: try c.decode(String.self, forKey: .poolId), idempotencyKey: try c.decode(String.self, forKey: .idempotencyKey), policySnapshot: try c.decode(AllocationPolicy.self, forKey: .policySnapshot), requestedDisplayMode: try c.contains(.requestedDisplayMode) ? c.decode(DisplayMode.self, forKey: .requestedDisplayMode) : nil)
     }
 
     public func validate() throws {
@@ -2170,6 +2228,9 @@ public struct SessionRequest: Codable, Equatable {
         if !self.idempotencyKey.isEmpty && self.idempotencyKey.utf8.count < 1 { throw ContractValidationError(field: "idempotency_key", code: "min_length") }
         if self.idempotencyKey.utf8.count > 256 { throw ContractValidationError(field: "idempotency_key", code: "max_length") }
         try self.policySnapshot.validate()
+        if let value = self.requestedDisplayMode {
+            try value.validate()
+        }
     }
 
     public static func decodeJSON(_ data: Data) throws -> Self { try JSONDecoder().decode(Self.self, from: data) }
diff --git a/openspec/changes/phase-3d-client-display-input/.openspec.yaml b/openspec/changes/phase-3d-client-display-input/.openspec.yaml
new file mode 100644
index 0000000..d7bc011
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/.openspec.yaml
@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-08-10
diff --git a/openspec/changes/phase-3d-client-display-input/design.md b/openspec/changes/phase-3d-client-display-input/design.md
new file mode 100644
index 0000000..87c5511
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/design.md
@@ -0,0 +1,54 @@
+## Context
+
+The JSON control schema is the generated-binding authority for broker requests
+and manifests, while VGI1 is the provider-neutral input payload. Both contracts
+are strict: old decoders reject unknown response fields and old gateways reject
+unknown VGI kinds. Phase 3D therefore needs optional fields plus explicit
+feature negotiation rather than a wire-version or protobuf change.
+
+## Goals / Non-Goals
+
+**Goals:**
+
+- Preserve legacy JSON shapes when display negotiation is absent.
+- Generate optional referenced objects correctly in Go, Rust, and Swift.
+- Define exact, bounded, cross-language absolute-pointer and scroll bytes.
+
+**Non-Goals:**
+
+- Server clamp policy, database persistence, or provider translation.
+- Live display renegotiation, provider packet exposure, or protobuf changes.
+
+## Decisions
+
+- Keep control wire version 1 and gate additions with exact feature IDs. This
+  avoids changing every legacy request while allowing strict clients to demand
+  the accepted display field.
+- Use one reusable `DisplayMode` with the existing provider-policy dimension
+  bounds. Optional referenced objects become Go pointers so `omitempty` is real;
+  Rust and Swift retain their existing optional generation.
+- Encode absolute pointer as four big-endian u16 values and scroll as two
+  big-endian i16 values in VGI1. Viewport coordinates are self-contained and
+  provider-neutral; provider scaling stays outside Protocol.
+- Leave protobuf unchanged because the observed broker and VGI consumers use
+  JSON and fixed byte frames, not generated protobuf messages.
+
+## Risks / Trade-offs
+
+- [Old strict consumers reject new response fields] → emit them only after
+  `display.request.v1` negotiation.
+- [New VGI kinds reach an old or unadvertised gateway] → reject before provider
+  translation unless the matching input feature is active.
+- [Generated Go optional values serialize as zero objects] → require pointers,
+  omission tests, and clean second generation.
+
+## Migration Plan
+
+Freeze a new never-reused Protocol RC after full verification. Server and Data
+Plane then pin that exact tag together. Legacy sessions omit all new fields and
+continue using existing input kinds.
+
+## Open Questions
+
+None at the Protocol boundary; policy clamp and Apollo translation remain
+consumer-owned work.
diff --git a/openspec/changes/phase-3d-client-display-input/proposal.md b/openspec/changes/phase-3d-client-display-input/proposal.md
new file mode 100644
index 0000000..c6485b0
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/proposal.md
@@ -0,0 +1,38 @@
+## Why
+
+The Phase 3D native client must request a bounded display mode and send
+provider-neutral absolute-pointer and high-resolution scroll input. The current
+wire contract exposes only policy-selected stream dimensions and rejects both
+new input kinds.
+
+## What Changes
+
+- Add one bounded `DisplayMode` object and optional display fields to session
+  request/session/manifest contracts while keeping control wire version 1.
+- Register `display.request.v1`, `input.absolute.v1`, and `input.scroll.v1` so
+  every new behavior is explicitly negotiated.
+- Extend VGI1 with exact absolute-pointer and signed scroll bodies while
+  preserving all existing kind encodings.
+- Require a new immutable Protocol release candidate after deterministic
+  Go/Rust/Swift generation and conformance pass; existing tags remain unchanged.
+
+## Capabilities
+
+### New Capabilities
+
+- `session-display-mode`: Optional feature-gated requested and effective display
+  mode disclosure for native session creation and manifests.
+
+### Modified Capabilities
+
+- `gateway-input-feedback`: Add negotiated provider-neutral absolute-pointer and
+  high-resolution scroll kinds to the existing sequenced input grammar.
+
+## Impact
+
+- JSON Schema, feature registry, VGI frame documentation, fixed conformance
+  fixtures, generated Go/Rust/Swift bindings, and strict validators.
+- Connection Server session persistence/allocation and Data Plane input
+  translation after consumers pin the immutable Protocol candidate.
+- Protobuf remains unchanged because no observed consumer uses it for these
+  JSON control or VGI payload paths.
diff --git a/openspec/changes/phase-3d-client-display-input/specs/gateway-input-feedback/spec.md b/openspec/changes/phase-3d-client-display-input/specs/gateway-input-feedback/spec.md
new file mode 100644
index 0000000..e879759
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/specs/gateway-input-feedback/spec.md
@@ -0,0 +1,33 @@
+## MODIFIED Requirements
+
+### Requirement: Typed sequenced input envelope
+The `input.sequenced.v1` payload SHALL begin with ASCII `VGI1`, a one-byte
+event kind, and one-byte payload length. It SHALL contain exactly one bounded
+keyboard, mouse-button, relative-mouse, UTF-8 scalar, controller-state,
+absolute-mouse, or high-resolution-scroll event. Absolute mouse kind `0x06`
+SHALL contain big-endian u16 x, y, viewport width, and viewport height, reject
+zero viewports and coordinates outside the viewport, and require negotiated
+`input.absolute.v1`. Scroll kind `0x07` SHALL contain big-endian signed i16
+vertical and horizontal deltas and require negotiated `input.scroll.v1`. False
+keyboard/mouse state and zeroed controller state are explicit releases.
+Unknown or unadvertised kinds, length mismatches, malformed UTF-8, unsupported
+controller indices, and reserved fields SHALL be rejected before provider
+translation.
+
+#### Scenario: Keyboard state change
+- **WHEN** a client sends a valid keyboard press or release envelope
+- **THEN** the gateway forwards the corresponding typed provider input on its
+  reliable keyboard channel and records the pressed state for cleanup.
+
+#### Scenario: Absolute pointer and scroll
+- **WHEN** an advertised client sends an in-viewport absolute coordinate or
+  signed scroll delta with the exact body length
+- **THEN** the gateway accepts the provider-neutral event without adding it to
+  pressed-state cleanup.
+
+#### Scenario: Invalid input envelope
+- **WHEN** a client sends an unknown or unadvertised kind, invalid length,
+  malformed UTF-8 scalar, zero viewport, out-of-range coordinate, or nonzero
+  reserved field
+- **THEN** the gateway rejects it without sending provider input or changing
+  pressed state.
diff --git a/openspec/changes/phase-3d-client-display-input/specs/session-display-mode/spec.md b/openspec/changes/phase-3d-client-display-input/specs/session-display-mode/spec.md
new file mode 100644
index 0000000..2a96810
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/specs/session-display-mode/spec.md
@@ -0,0 +1,35 @@
+## ADDED Requirements
+
+### Requirement: Bounded display mode contract
+The Protocol SHALL define `DisplayMode` with required integer
+`resolution_width` from 320 through 16384, `resolution_height` from 200 through
+8640, and `fps` from 1 through 240, rejecting missing, unknown, or out-of-range
+fields.
+
+#### Scenario: Valid display mode
+- **WHEN** a client encodes a 2560 by 1440 display mode at 120 FPS
+- **THEN** generated Go, Rust, and Swift bindings accept the same exact values.
+
+#### Scenario: Invalid display mode
+- **WHEN** any dimension or FPS is outside its bound or an unknown field exists
+- **THEN** strict Protocol validation rejects the object.
+
+### Requirement: Feature-gated optional display disclosure
+`SessionRequest.requested_display_mode`,
+`BrokerSession.requested_display_mode`,
+`BrokerSession.effective_display_mode`, and `ManifestProfile.display_mode`
+SHALL be optional references to `DisplayMode`. Go bindings SHALL use pointers
+with JSON omission and Rust/Swift bindings SHALL use optionals. A client MUST
+send the request only after `display.request.v1` negotiation, and a
+display-aware manifest MUST contain the accepted mode. Legacy requests SHALL
+produce legacy response shapes without these fields.
+
+#### Scenario: Legacy request remains unchanged
+- **WHEN** a client omits `requested_display_mode`
+- **THEN** encoding omits the field and compatible Server responses omit all
+  display-mode fields.
+
+#### Scenario: Display-aware request discloses acceptance
+- **WHEN** a negotiated client sends a valid requested mode
+- **THEN** session responses preserve the requested mode and the allocated
+  manifest includes the Server-accepted mode.
diff --git a/openspec/changes/phase-3d-client-display-input/tasks.md b/openspec/changes/phase-3d-client-display-input/tasks.md
new file mode 100644
index 0000000..3abf1c7
--- /dev/null
+++ b/openspec/changes/phase-3d-client-display-input/tasks.md
@@ -0,0 +1,17 @@
+## 1. Contract sources
+
+- [x] 1.1 Add failing Go omission/bounds tests and fixed absolute/scroll vectors.
+- [x] 1.2 Add the bounded display schema, optional generated references, and feature registrations.
+- [x] 1.3 Extend the VGI frame grammar and Python/Go/Rust/Swift classifiers without changing existing kinds.
+
+## 2. Deterministic verification
+
+- [x] 2.1 Regenerate Go/Rust/Swift bindings and pass focused Go, frame, source, binding, and strict-contract checks.
+- [x] 2.2 Run the complete Protocol verifier with isolated compiler caches.
+- [x] 2.3 Regenerate a second time, confirm zero drift, and inspect the exact source/generated diff.
+
+## 3. Freeze
+
+- [ ] 3.1 Commit the verified source and generated bindings as one unsigned capability-sized change.
+- [ ] 3.2 Verify the next Phase 3D Protocol RC name is unused locally and remotely, then create one local immutable candidate tag without publishing it.
+- [ ] 3.3 Reconcile and archive this OpenSpec change after the immutable candidate is frozen.
diff --git a/registries/features.json b/registries/features.json
index 7601b41..e4712b7 100644
--- a/registries/features.json
+++ b/registries/features.json
@@ -3,6 +3,9 @@
   "features": [
     {"id": "control.v1", "direction": "bidirectional", "max_frame_bytes": 65536},
     {"id": "events.resume.v1", "direction": "server-to-client", "max_frame_bytes": 65536},
-    {"id": "clipboard.text.v1", "direction": "bidirectional", "max_frame_bytes": 65536}
+    {"id": "clipboard.text.v1", "direction": "bidirectional", "max_frame_bytes": 65536},
+    {"id": "display.request.v1", "direction": "client-to-server", "max_frame_bytes": 65536},
+    {"id": "input.absolute.v1", "direction": "client-to-server", "max_frame_bytes": 14},
+    {"id": "input.scroll.v1", "direction": "client-to-server", "max_frame_bytes": 10}
   ]
 }
diff --git a/schemas/control-v1.schema.json b/schemas/control-v1.schema.json
index 2d79078..c899729 100644
--- a/schemas/control-v1.schema.json
+++ b/schemas/control-v1.schema.json
@@ -178,6 +178,16 @@
         "refresh_expires_at": {"type": "string", "format": "date-time", "maxLength": 64}
       }
     },
+    "DisplayMode": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["resolution_width", "resolution_height", "fps"],
+      "properties": {
+        "resolution_width": {"type": "integer", "minimum": 320, "maximum": 16384},
+        "resolution_height": {"type": "integer", "minimum": 200, "maximum": 8640},
+        "fps": {"type": "integer", "minimum": 1, "maximum": 240}
+      }
+    },
     "SessionRequest": {
       "type": "object",
       "additionalProperties": false,
@@ -187,7 +197,8 @@
         "device_key_id": {"type": "string", "minLength": 1, "maxLength": 128},
         "pool_id": {"type": "string", "minLength": 1, "maxLength": 128},
         "idempotency_key": {"type": "string", "minLength": 1, "maxLength": 256},
-        "policy_snapshot": {"$ref": "#/$defs/AllocationPolicy"}
+        "policy_snapshot": {"$ref": "#/$defs/AllocationPolicy"},
+        "requested_display_mode": {"$ref": "#/$defs/DisplayMode"}
       }
     },
     "ReconnectRequest": {
@@ -219,7 +230,9 @@
         "correlation_id": {"type": "string", "minLength": 1, "maxLength": 128},
         "requested_at": {"type": "string", "format": "date-time", "maxLength": 64},
         "ended_at": {"type": "string", "format": "date-time", "maxLength": 64},
-        "version": {"type": "integer", "minimum": 1}
+        "version": {"type": "integer", "minimum": 1},
+        "requested_display_mode": {"$ref": "#/$defs/DisplayMode"},
+        "effective_display_mode": {"$ref": "#/$defs/DisplayMode"}
       }
     },
     "AllocationPolicy": {
@@ -279,7 +292,8 @@
       "required": ["id", "bounds"],
       "properties": {
         "id": {"type": "string", "minLength": 1, "maxLength": 128},
-        "bounds": {"$ref": "#/$defs/ManifestBounds"}
+        "bounds": {"$ref": "#/$defs/ManifestBounds"},
+        "display_mode": {"$ref": "#/$defs/DisplayMode"}
       }
     },
     "ManifestBounds": {
diff --git a/tests/go/protocol_test.go b/tests/go/protocol_test.go
index da9771b..effb479 100644
--- a/tests/go/protocol_test.go
+++ b/tests/go/protocol_test.go
@@ -1,6 +1,7 @@
 package protocol_test
 
 import (
+	"bytes"
 	"reflect"
 	"strings"
 	"testing"
@@ -22,6 +23,83 @@ func TestManifestRejectsForbiddenAndUnknownFields(t *testing.T) {
 	}
 }
 
+func TestDisplayModeIsOptionalStrictAndBounded(t *testing.T) {
+	displayType := reflect.TypeOf(protocol.DisplayMode{})
+	for _, field := range []struct {
+		owner reflect.Type
+		name  string
+	}{
+		{reflect.TypeOf(protocol.SessionRequest{}), "RequestedDisplayMode"},
+		{reflect.TypeOf(protocol.BrokerSession{}), "RequestedDisplayMode"},
+		{reflect.TypeOf(protocol.BrokerSession{}), "EffectiveDisplayMode"},
+		{reflect.TypeOf(protocol.ManifestProfile{}), "DisplayMode"},
+	} {
+		actual, ok := field.owner.FieldByName(field.name)
+		if !ok || actual.Type.Kind() != reflect.Pointer || actual.Type.Elem() != displayType {
+			t.Fatalf("%s.%s must be *DisplayMode, got %v", field.owner, field.name, actual.Type)
+		}
+	}
+
+	request := protocol.SessionRequest{
+		ClientDeviceID: "device-1", DeviceKeyID: "key-1", PoolID: "pool-1", IdempotencyKey: "request-1",
+		PolicySnapshot: protocol.AllocationPolicy{
+			MinimumKbps: 1000, TargetKbps: 2000, MaximumKbps: 3000, Tier: "standard",
+			Audience: "versevdi-gateway", Protocol: "verse", ProtocolVersion: 1,
+			GrantTTLSeconds: 60, ReservationLeaseSeconds: 300,
+		},
+	}
+	legacy, err := protocol.EncodeSessionRequest(request)
+	if err != nil {
+		t.Fatalf("EncodeSessionRequest legacy request: %v", err)
+	}
+	if bytes.Contains(legacy, []byte("requested_display_mode")) {
+		t.Fatalf("legacy request disclosed an absent display mode: %s", legacy)
+	}
+
+	mode := protocol.DisplayMode{ResolutionWidth: 2560, ResolutionHeight: 1440, Fps: 120}
+	request.RequestedDisplayMode = &mode
+	aware, err := protocol.EncodeSessionRequest(request)
+	if err != nil || !bytes.Contains(aware, []byte(`"requested_display_mode":{"resolution_width":2560,"resolution_height":1440,"fps":120}`)) {
+		t.Fatalf("display-aware request = %s, err = %v", aware, err)
+	}
+	decoded, err := protocol.DecodeSessionRequest(aware)
+	if err != nil || decoded.RequestedDisplayMode == nil || *decoded.RequestedDisplayMode != mode {
+		t.Fatalf("DecodeSessionRequest display mode = %+v, err = %v", decoded.RequestedDisplayMode, err)
+	}
+	nullMode := bytes.Replace(aware, []byte(`{"resolution_width":2560,"resolution_height":1440,"fps":120}`), []byte("null"), 1)
+	if _, err := protocol.DecodeSessionRequest(nullMode); err == nil {
+		t.Fatalf("DecodeSessionRequest accepted explicit null display mode: %s", nullMode)
+	}
+
+	profile := protocol.ManifestProfile{
+		ID:     "standard",
+		Bounds: protocol.ManifestBounds{MinimumKbps: 1000, TargetKbps: 2000, MaximumKbps: 3000},
+	}
+	legacyProfile, err := protocol.EncodeManifestProfile(profile)
+	if err != nil || bytes.Contains(legacyProfile, []byte("display_mode")) {
+		t.Fatalf("legacy profile = %s, err = %v", legacyProfile, err)
+	}
+	profile.DisplayMode = &mode
+	awareProfile, err := protocol.EncodeManifestProfile(profile)
+	if err != nil || !bytes.Contains(awareProfile, []byte(`"display_mode":{"resolution_width":2560,"resolution_height":1440,"fps":120}`)) {
+		t.Fatalf("display-aware profile = %s, err = %v", awareProfile, err)
+	}
+
+	for _, invalid := range []string{
+		`{"resolution_width":319,"resolution_height":1440,"fps":120}`,
+		`{"resolution_width":16385,"resolution_height":1440,"fps":120}`,
+		`{"resolution_width":2560,"resolution_height":199,"fps":120}`,
+		`{"resolution_width":2560,"resolution_height":8641,"fps":120}`,
+		`{"resolution_width":2560,"resolution_height":1440,"fps":0}`,
+		`{"resolution_width":2560,"resolution_height":1440,"fps":241}`,
+		`{"resolution_width":2560,"resolution_height":1440,"fps":120,"unknown":true}`,
+	} {
+		if _, err := protocol.DecodeDisplayMode([]byte(invalid)); err == nil {
+			t.Fatalf("DecodeDisplayMode accepted %s", invalid)
+		}
+	}
+}
+
 func TestPageInfoRejectsOutOfBoundsLimit(t *testing.T) {
 	if _, err := protocol.DecodePageInfo([]byte(`{"limit":101,"next_cursor":""}`)); err == nil {
 		t.Fatal("DecodePageInfo accepted limit above the contract maximum")
diff --git a/tools/generate.py b/tools/generate.py
index 8f98dc6..4e80f5b 100644
--- a/tools/generate.py
+++ b/tools/generate.py
@@ -160,7 +160,11 @@ def go_validation(definition: dict[str, Any]) -> list[str]:
                 lines.append(f"\tfor index := range v.{field} {{ if err := v.{field}[index].Validate(); err != nil {{ violations = append(violations, FieldViolation{{Field: fmt.Sprintf(\"{prop_name}[%d]\", index), Code: \"invalid_item\"}}) }} }}")
         reference = ref_name(prop)
         if reference:
-            lines.append(f"\tif err := v.{field}.Validate(); err != nil {{ violations = append(violations, FieldViolation{{Field: \"{prop_name}\", Code: \"invalid_object\"}}) }}")
+            validation = f"if err := v.{field}.Validate(); err != nil {{ violations = append(violations, FieldViolation{{Field: \"{prop_name}\", Code: \"invalid_object\"}}) }}"
+            if prop_name not in required:
+                lines.append(f"\tif v.{field} != nil {{ {validation} }}")
+            else:
+                lines.append(f"\t{validation}")
     if name in {"AllocationPolicy", "ManifestBounds"}:
         lines.append("\tif v.MinimumKbps > v.TargetKbps || v.TargetKbps > v.MaximumKbps { violations = append(violations, FieldViolation{Field: \"bounds\", Code: \"invalid_order\"}) }")
     if name == "GatewayRegistration":
@@ -212,7 +216,10 @@ def generate_go(defs: dict[str, dict[str, Any]], schema_hash: str, version: str,
         required = set(definition.get("required", []))
         for prop_name, prop in definition.get("properties", {}).items():
             tag = prop_name + (",omitempty" if prop_name not in required else "")
-            out.append(f"\t{go_field(prop_name)} {prop_type(prop, 'go')} `json:\"{tag}\"`")
+            typ = prop_type(prop, "go")
+            if prop_name not in required and ref_name(prop):
+                typ = "*" + typ
+            out.append(f"\t{go_field(prop_name)} {typ} `json:\"{tag}\"`")
         out.extend(["}", ""])
     for name in sorted(defs):
         out.append(f"func (v {name}) Validate() error {{")
@@ -234,6 +241,11 @@ def generate_go(defs: dict[str, dict[str, Any]], schema_hash: str, version: str,
                 % (prop_name, prop_name)
             )
         for prop_name, prop in defs[name].get("properties", {}).items():
+            if prop_name not in required_fields and ref_name(prop):
+                out.append(
+                    '\tif raw, ok := fields["%s"]; ok && bytes.Equal(bytes.TrimSpace(raw), []byte("null")) { return value, ValidationError{Violations: []FieldViolation{{Field: "%s", Code: "invalid_object"}}} }'
+                    % (prop_name, prop_name)
+                )
             if "x-max-bytes" in prop and prop.get("type") != "string":
                 out.append(
                     '\tif raw, ok := fields["%s"]; ok && len(raw) > %d { return value, ValidationError{Violations: []FieldViolation{{Field: "%s", Code: "max_bytes"}}} }'
@@ -603,6 +615,8 @@ def generate_swift(defs: dict[str, dict[str, Any]], schema_hash: str, compatibil
             typ = swift_type(prop)
             if prop_name in required:
                 decoded.append(f"{field}: try c.decode({typ}.self, forKey: .{field})")
+            elif ref_name(prop):
+                decoded.append(f"{field}: try c.contains(.{field}) ? c.decode({typ}.self, forKey: .{field}) : nil")
             else:
                 decoded.append(f"{field}: try c.decodeIfPresent({typ}.self, forKey: .{field})")
         out.append(f"        try self.init({', '.join(decoded)})")
diff --git a/tools/go-conformance/main.go b/tools/go-conformance/main.go
index 93eba83..9acac0b 100644
--- a/tools/go-conformance/main.go
+++ b/tools/go-conformance/main.go
@@ -125,10 +125,12 @@ func evaluate(kind, input string) string {
 		}
 		return "valid"
 	case "tunnel":
-		if (parts["offered"] == "1" || parts["offered"] == "0" || parts["offered"] == "-1") && parts["feature"] == "control.v1" {
+		feature := parts["feature"]
+		registered := feature == "control.v1" || feature == "display.request.v1" || feature == "input.absolute.v1" || feature == "input.scroll.v1"
+		if (parts["offered"] == "1" || parts["offered"] == "0" || parts["offered"] == "-1") && registered {
 			return "valid"
 		}
-		if parts["feature"] != "control.v1" {
+		if !registered {
 			return "invalid:unsupported_feature"
 		}
 		return "invalid:unsupported_version"
@@ -226,6 +228,19 @@ func classifyGatewayInput(encoded string) string {
 				}
 			}
 		}
+	case 6:
+		if len(body) != 8 {
+			return "invalid:length"
+		}
+		x, y := uint16(body[0])<<8|uint16(body[1]), uint16(body[2])<<8|uint16(body[3])
+		width, height := uint16(body[4])<<8|uint16(body[5]), uint16(body[6])<<8|uint16(body[7])
+		if width == 0 || height == 0 || x >= width || y >= height {
+			return "invalid:field"
+		}
+	case 7:
+		if len(body) != 4 {
+			return "invalid:length"
+		}
 	default:
 		return "invalid:kind"
 	}
diff --git a/tools/native_conformance.rs b/tools/native_conformance.rs
index ce14da5..d9391c2 100644
--- a/tools/native_conformance.rs
+++ b/tools/native_conformance.rs
@@ -47,8 +47,8 @@ fn evaluate(kind: &str, input: &str) -> &'static str {
             || !values.contains_key("correlation_id") => "invalid:required",
         "event" => "valid",
         "tunnel" if matches!(values.get("offered").map(String::as_str), Some("1") | Some("0") | Some("-1"))
-            && values.get("feature").map(String::as_str) == Some("control.v1") => "valid",
-        "tunnel" if values.get("feature").map(String::as_str) != Some("control.v1") => {
+            && matches!(values.get("feature").map(String::as_str), Some("control.v1") | Some("display.request.v1") | Some("input.absolute.v1") | Some("input.scroll.v1")) => "valid",
+        "tunnel" if !matches!(values.get("feature").map(String::as_str), Some("control.v1") | Some("display.request.v1") | Some("input.absolute.v1") | Some("input.scroll.v1")) => {
             "invalid:unsupported_feature"
         }
         "tunnel" => "invalid:unsupported_version",
@@ -110,6 +110,16 @@ fn classify_gateway_input(encoded: &str) -> &'static str {
         5 if body[0] > 15 => "invalid:field",
         5 if body[1] == 0 && body[2] == 0 && body[3..].iter().any(|value| *value != 0) => "invalid:field",
         5 => "valid",
+        6 if body.len() != 8 => "invalid:length",
+        6 => {
+            let x = u16::from_be_bytes([body[0], body[1]]);
+            let y = u16::from_be_bytes([body[2], body[3]]);
+            let width = u16::from_be_bytes([body[4], body[5]]);
+            let height = u16::from_be_bytes([body[6], body[7]]);
+            if width != 0 && height != 0 && x < width && y < height { "valid" } else { "invalid:field" }
+        }
+        7 if body.len() == 4 => "valid",
+        7 => "invalid:length",
         _ => "invalid:kind",
     }
 }
diff --git a/tools/native_conformance.swift b/tools/native_conformance.swift
index b73512b..72e80d0 100644
--- a/tools/native_conformance.swift
+++ b/tools/native_conformance.swift
@@ -27,8 +27,9 @@ func evaluate(_ kind: String, _ input: String) -> String {
         guard let sequence = Int(values["sequence"] ?? ""), sequence > 0, values["correlation_id"] != nil else { return "invalid:required" }
         return "valid"
     case "tunnel":
-        if ["1", "0", "-1"].contains(values["offered"] ?? "") && values["feature"] == "control.v1" { return "valid" }
-        return values["feature"] == "control.v1" ? "invalid:unsupported_version" : "invalid:unsupported_feature"
+        let registered = ["control.v1", "display.request.v1", "input.absolute.v1", "input.scroll.v1"].contains(values["feature"] ?? "")
+        if ["1", "0", "-1"].contains(values["offered"] ?? "") && registered { return "valid" }
+        return registered ? "invalid:unsupported_version" : "invalid:unsupported_feature"
     case "datagram": return classifyDatagram(values["hex"] ?? "")
     case "gateway_input": return classifyGatewayInput(values["hex"] ?? "")
     case "gateway_feedback": return classifyGatewayFeedback(values["hex"] ?? "")
@@ -82,6 +83,14 @@ func classifyGatewayInput(_ encoded: String) -> String {
         guard body[0] <= 15 else { return "invalid:field" }
         guard body[1] != 0 || body[2] != 0 || body.dropFirst(3).allSatisfy({ $0 == 0 }) else { return "invalid:field" }
         return "valid"
+    case 6:
+        guard body.count == 8 else { return "invalid:length" }
+        let x = Int(body[0]) * 256 + Int(body[1])
+        let y = Int(body[2]) * 256 + Int(body[3])
+        let width = Int(body[4]) * 256 + Int(body[5])
+        let height = Int(body[6]) * 256 + Int(body[7])
+        return width > 0 && height > 0 && x < width && y < height ? "valid" : "invalid:field"
+    case 7: return body.count == 4 ? "valid" : "invalid:length"
     default: return "invalid:kind"
     }
 }
diff --git a/tools/test_generated_contracts.py b/tools/test_generated_contracts.py
index 3e7e562..0b9aee9 100644
--- a/tools/test_generated_contracts.py
+++ b/tools/test_generated_contracts.py
@@ -103,6 +103,44 @@ do {
     )
     fatalError("invalid allocation bounds were accepted")
 } catch { }
+let displayMode = try DisplayMode(resolutionWidth: 2560, resolutionHeight: 1440, fps: 120)
+for invalid in [
+    { try DisplayMode(resolutionWidth: 319, resolutionHeight: 1440, fps: 120) },
+    { try DisplayMode(resolutionWidth: 2560, resolutionHeight: 199, fps: 120) },
+    { try DisplayMode(resolutionWidth: 2560, resolutionHeight: 1440, fps: 241) },
+] {
+    do {
+        _ = try invalid()
+        fatalError("invalid display mode was accepted")
+    } catch { }
+}
+let allocationPolicy = try AllocationPolicy(
+    minimumKbps: 1000, targetKbps: 2000, maximumKbps: 3000, tier: "standard",
+    audience: "versevdi-gateway", protocolValue: "verse", protocolVersion: 1,
+    grantTtlSeconds: 60, reservationLeaseSeconds: 300
+)
+let legacyDisplayRequest = try SessionRequest(
+    clientDeviceId: "device-1", deviceKeyId: "key-1", poolId: "pool-1",
+    idempotencyKey: "request-1", policySnapshot: allocationPolicy,
+    requestedDisplayMode: nil
+).encodeJSON()
+guard !String(data: legacyDisplayRequest, encoding: .utf8)!.contains("requested_display_mode") else {
+    fatalError("legacy request encoded an absent display mode")
+}
+let displayRequest = try SessionRequest(
+    clientDeviceId: "device-1", deviceKeyId: "key-1", poolId: "pool-1",
+    idempotencyKey: "request-1", policySnapshot: allocationPolicy,
+    requestedDisplayMode: displayMode
+)
+guard try SessionRequest.decodeJSON(displayRequest.encodeJSON()).requestedDisplayMode == displayMode else {
+    fatalError("display mode did not round-trip")
+}
+var nullDisplayRequest = try JSONSerialization.jsonObject(with: displayRequest.encodeJSON()) as! [String: Any]
+nullDisplayRequest["requested_display_mode"] = NSNull()
+do {
+    _ = try SessionRequest.decodeJSON(try JSONSerialization.data(withJSONObject: nullDisplayRequest))
+    fatalError("explicit null display mode was accepted")
+} catch { }
 let streamPolicy = try ProviderStreamPolicy(
     resolutionWidth: 2560, resolutionHeight: 1440, fps: 120,
     codec: "HEVC", bitrateKbps: 40000, audioEnabled: true
@@ -218,6 +256,24 @@ fn main() {
     assert!(AllocationPolicy::new(
         100, 50, 25, "standard".into(), "audience".into(), "verse".into(), 1, 60, 300,
     ).is_err());
+    let display_mode = DisplayMode::new(2560, 1440, 120).unwrap();
+    assert!(DisplayMode::new(319, 1440, 120).is_err());
+    assert!(DisplayMode::new(2560, 199, 120).is_err());
+    assert!(DisplayMode::new(2560, 1440, 241).is_err());
+    let allocation_policy = AllocationPolicy::new(
+        1000, 2000, 3000, "standard".into(), "versevdi-gateway".into(),
+        "verse".into(), 1, 60, 300,
+    ).unwrap();
+    let legacy_display_request = SessionRequest::new(
+        "device-1".into(), "key-1".into(), "pool-1".into(), "request-1".into(),
+        allocation_policy.clone(), None,
+    ).unwrap();
+    assert!(legacy_display_request.requestedDisplayMode().is_none());
+    let display_request = SessionRequest::new(
+        "device-1".into(), "key-1".into(), "pool-1".into(), "request-1".into(),
+        allocation_policy, Some(display_mode.clone()),
+    ).unwrap();
+    assert_eq!(display_request.requestedDisplayMode(), &Some(display_mode));
     assert!(ProviderStreamPolicy::new(
         2560, 1440, 120, "HEVC".into(), 40000, true,
     ).is_ok());
diff --git a/tools/validate.py b/tools/validate.py
index 5344fc0..3feeb97 100644
--- a/tools/validate.py
+++ b/tools/validate.py
@@ -36,6 +36,24 @@ def main() -> int:
             maximum = entry.get("max_frame_bytes", entry.get("max_payload_bytes"))
             assert isinstance(maximum, int) and 1 <= maximum <= maximum_bound
 
+    feature_registry = json.loads((ROOT / "registries/features.json").read_text(encoding="utf-8"))
+    registered_features = {entry["id"] for entry in feature_registry["features"]}
+    assert {"display.request.v1", "input.absolute.v1", "input.scroll.v1"}.issubset(registered_features)
+
+    display_mode = defs["DisplayMode"]
+    assert display_mode["required"] == ["resolution_width", "resolution_height", "fps"]
+    assert display_mode["properties"]["resolution_width"] == {"type": "integer", "minimum": 320, "maximum": 16384}
+    assert display_mode["properties"]["resolution_height"] == {"type": "integer", "minimum": 200, "maximum": 8640}
+    assert display_mode["properties"]["fps"] == {"type": "integer", "minimum": 1, "maximum": 240}
+    for owner, field in (
+        ("SessionRequest", "requested_display_mode"),
+        ("BrokerSession", "requested_display_mode"),
+        ("BrokerSession", "effective_display_mode"),
+        ("ManifestProfile", "display_mode"),
+    ):
+        assert field not in defs[owner]["required"]
+        assert defs[owner]["properties"][field] == {"$ref": "#/$defs/DisplayMode"}
+
     manifest = json.loads((ROOT / "fixtures/valid/manifest.json").read_text(encoding="utf-8"))
     assert set(manifest).issubset(set(defs["ConnectionManifest"]["properties"]))
     forbidden = json.loads((ROOT / "fixtures/invalid/manifest-provider-field.json").read_text(encoding="utf-8"))
diff --git a/tools/validate_gateway_envelopes.py b/tools/validate_gateway_envelopes.py
index a7bb4ea..2d830bb 100644
--- a/tools/validate_gateway_envelopes.py
+++ b/tools/validate_gateway_envelopes.py
@@ -37,6 +37,13 @@ def classify_input(raw: bytes) -> str:
             return "invalid:field"
         active_mask = int.from_bytes(body[1:3], "big")
         return "valid" if active_mask or not any(body[3:]) else "invalid:field"
+    if kind == 6:
+        if len(body) != 8:
+            return "invalid:length"
+        x, y, width, height = (int.from_bytes(body[index:index + 2], "big") for index in range(0, 8, 2))
+        return "valid" if width and height and x < width and y < height else "invalid:field"
+    if kind == 7:
+        return "valid" if len(body) == 4 else "invalid:length"
     return "invalid:kind"