diff --git a/.github/workflows/conformance.yml b/.github/workflows/conformance.yml
index cca700d..feb5000 100644
--- a/.github/workflows/conformance.yml
+++ b/.github/workflows/conformance.yml
@@ -68,9 +68,9 @@ jobs:
         uses: actions/setup-node@2028fbc5c25fe9cf00d9f06a71cc4710d4507903 # v6.0.0
         with:
           node-version: 22
-      - name: Run conformance tests
+      - name: Run conformance tests (full suite)
         run: |
           npx -y "@modelcontextprotocol/conformance@${CONFORMANCE_VERSION}" client \
             --command "go run ./conformance/everything-client" \
-            --suite core \
+            --suite all \
             --expected-failures ./conformance/baseline.yml
diff --git a/conformance/baseline.yml b/conformance/baseline.yml
index 9d7bef8..49f68b6 100644
--- a/conformance/baseline.yml
+++ b/conformance/baseline.yml
@@ -1,2 +1,13 @@
 server: [] # All tests pass!
-client: [] # All tests pass!
+
+client:
+  # OAuth mechanisms not yet implemented by the Go MCP SDK.
+  - auth/client-credentials-basic
+  - auth/client-credentials-jwt
+  - auth/enterprise-managed-authorization
+
+  # Upstream conformance mock inconsistency: the scenario's hand-rolled
+  # server/discover handler advertises "2026-07-28" but delegates every
+  # other method to a pinned @modelcontextprotocol/sdk that rejects that
+  # version at the HTTP layer.
+  - json-schema-ref-no-deref
diff --git a/conformance/everything-client/main.go b/conformance/everything-client/main.go
index 55a55ad..3776522 100644
--- a/conformance/everything-client/main.go
+++ b/conformance/everything-client/main.go
@@ -45,32 +45,43 @@ func registerScenario(name string, handler scenarioHandler) {
 func init() {
 	registerScenario("initialize", runBasicClient)
 	registerScenario("tools_call", runToolsCallClient)
+	registerScenario("request-metadata", runRequestMetadataClient)
 	registerScenario("elicitation-sep1034-client-defaults", runElicitationDefaultsClient)
 	registerScenario("sse-retry", runSSERetryClient)
+	registerScenario("json-schema-ref-no-deref", runJSONSchemaRefNoDerefClient)
+	registerScenario("sep-2322-client-request-state", runMrtrClient)
+	registerScenario("http-standard-headers", runHTTPStandardHeadersClient)
+	registerScenario("http-custom-headers", runHTTPCustomHeadersClient)
+	registerScenario("http-invalid-tool-headers", runHTTPInvalidToolHeadersClient)
 
 	authScenarios := []string{
 		"auth/2025-03-26-oauth-metadata-backcompat",
 		"auth/2025-03-26-oauth-endpoint-fallback",
+		"auth/authorization-server-migration",
 		"auth/basic-cimd",
+		"auth/iss-normalized",
+		"auth/iss-not-advertised",
+		"auth/iss-supported",
+		"auth/iss-supported-missing",
+		"auth/iss-unexpected",
+		"auth/iss-wrong-issuer",
 		"auth/metadata-default",
+		"auth/metadata-issuer-mismatch",
 		"auth/metadata-var1",
 		"auth/metadata-var2",
 		"auth/metadata-var3",
+		"auth/offline-access-not-supported",
+		"auth/offline-access-scope",
 		"auth/pre-registration",
 		"auth/resource-mismatch",
-		"auth/scope-from-www-authenticate",
 		"auth/scope-from-scopes-supported",
+		"auth/scope-from-www-authenticate",
 		"auth/scope-omitted-when-undefined",
-		"auth/scope-step-up",
 		"auth/scope-retry-limit",
+		"auth/scope-step-up",
 		"auth/token-endpoint-auth-basic",
-		"auth/token-endpoint-auth-post",
 		"auth/token-endpoint-auth-none",
-		"auth/iss-supported",
-		"auth/iss-not-advertised",
-		"auth/iss-supported-missing",
-		"auth/iss-wrong-issuer",
-		"auth/iss-unexpected",
+		"auth/token-endpoint-auth-post",
 	}
 	for _, scenario := range authScenarios {
 		registerScenario(scenario, runAuthClient)
@@ -293,6 +304,198 @@ func runAuthClient(ctx context.Context, serverURL string, configCtx map[string]a
 	return nil
 }
 
+// ============================================================================
+// request-metadata scenario (SEP-2575)
+// ============================================================================
+
+// runRequestMetadataClient exercises the SEP-2575 wire-level negotiation:
+// every request must carry the MCP-Protocol-Version header and the per-request
+// _meta envelope, and the client must retry with a supported version when its
+// first choice is rejected with -32022. The Go SDK's Connect() drives
+// server/discover unconditionally for 2026-07-28, which is exactly that
+// mechanism.
+func runRequestMetadataClient(ctx context.Context, serverURL string, _ map[string]any) error {
+	session, err := connectToServer(ctx, serverURL)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+	return nil
+}
+
+// ============================================================================
+// json-schema-ref-no-deref scenario (SEP-2106)
+// ============================================================================
+
+// runJSONSchemaRefNoDerefClient asserts that listTools does not dereference
+// network $ref URLs in tool schemas. The Go SDK never fetches external refs;
+// a plain connect → listTools is sufficient — if the SDK ever regressed and
+// tried to GET the canary URL the conformance referee would record the
+// failure.
+func runJSONSchemaRefNoDerefClient(ctx context.Context, serverURL string, _ map[string]any) error {
+	session, err := connectToServer(ctx, serverURL)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+
+	_, _ = session.ListTools(ctx, nil)
+	return nil
+}
+
+// ============================================================================
+// SEP-2322 multi-round-trip client scenario
+// ============================================================================
+
+// runMrtrClient drives the SEP-2322 client-request-state scenario. The
+// SDK's built-in client-side MRTR middleware transparently fulfills embedded
+// elicitation requests via ElicitationHandler and echoes requestState.
+func runMrtrClient(ctx context.Context, serverURL string, _ map[string]any) error {
+	elicitationHandler := func(context.Context, *mcp.ElicitRequest) (*mcp.ElicitResult, error) {
+		return &mcp.ElicitResult{
+			Action:  "accept",
+			Content: map[string]any{"confirmed": true},
+		}, nil
+	}
+	session, err := connectToServer(ctx, serverURL,
+		withClientOptions(&mcp.ClientOptions{
+			Capabilities:       &mcp.ClientCapabilities{Elicitation: &mcp.ElicitationCapabilities{}},
+			ElicitationHandler: elicitationHandler,
+		}),
+	)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+
+	toolNames := []string{
+		"test_mrtr_echo_state",
+		"test_mrtr_no_state",
+		"test_mrtr_unrelated",
+		"test_mrtr_no_result_type",
+	}
+	for _, name := range toolNames {
+		if _, err := session.CallTool(ctx, &mcp.CallToolParams{
+			Name:      name,
+			Arguments: map[string]any{},
+		}); err != nil {
+			log.Printf("CallTool(%q) rejected locally (expected for some cases): %v", name, err)
+		}
+	}
+	return nil
+}
+
+// ============================================================================
+// SEP-2243 HTTP header scenarios
+// ============================================================================
+
+// runHTTPStandardHeadersClient (SEP-2243 standard headers) drives tools,
+// resources and prompts once each so the referee sees Mcp-Method / Mcp-Name
+// headers on every verb the SDK supports.
+func runHTTPStandardHeadersClient(ctx context.Context, serverURL string, _ map[string]any) error {
+	session, err := connectToServer(ctx, serverURL)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+
+	if tools, err := session.ListTools(ctx, nil); err == nil && len(tools.Tools) > 0 {
+		_, _ = session.CallTool(ctx, &mcp.CallToolParams{
+			Name:      tools.Tools[0].Name,
+			Arguments: map[string]any{},
+		})
+	}
+	if res, err := session.ListResources(ctx, nil); err == nil && len(res.Resources) > 0 {
+		_, _ = session.ReadResource(ctx, &mcp.ReadResourceParams{URI: res.Resources[0].URI})
+	}
+	if prompts, err := session.ListPrompts(ctx, nil); err == nil && len(prompts.Prompts) > 0 {
+		_, _ = session.GetPrompt(ctx, &mcp.GetPromptParams{
+			Name:      prompts.Prompts[0].Name,
+			Arguments: map[string]string{},
+		})
+	}
+	return nil
+}
+
+// runHTTPCustomHeadersClient (SEP-2243 custom headers) lists tools (so the
+// SDK caches inputSchema and its x-mcp-header annotations), then makes the
+// runner-supplied tool calls so the referee validates the Mcp-Param-*
+// headers.
+func runHTTPCustomHeadersClient(ctx context.Context, serverURL string, configCtx map[string]any) error {
+	session, err := connectToServer(ctx, serverURL)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+
+	if _, err := session.ListTools(ctx, nil); err != nil {
+		return fmt.Errorf("session.ListTools(): %v", err)
+	}
+	for _, call := range readToolCallsContext(configCtx) {
+		if _, err := session.CallTool(ctx, &mcp.CallToolParams{
+			Name:      call.Name,
+			Arguments: call.Arguments,
+		}); err != nil {
+			log.Printf("CallTool(%q): %v", call.Name, err)
+		}
+	}
+	return nil
+}
+
+// runHTTPInvalidToolHeadersClient (SEP-2243 invalid-tool filtering) lists
+// tools — a correct SDK leaves only the valid ones — then calls each survivor
+// so the referee records SUCCESS for every excluded tool never called.
+func runHTTPInvalidToolHeadersClient(ctx context.Context, serverURL string, _ map[string]any) error {
+	session, err := connectToServer(ctx, serverURL)
+	if err != nil {
+		return err
+	}
+	defer session.Close()
+
+	tools, err := session.ListTools(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("session.ListTools(): %v", err)
+	}
+	for _, tool := range tools.Tools {
+		_, err := session.CallTool(ctx, &mcp.CallToolParams{
+			Name:      tool.Name,
+			Arguments: map[string]any{"region": "us-west1"},
+		})
+		if err != nil {
+			log.Printf("call %q rejected: %v", tool.Name, err)
+		}
+	}
+	return nil
+}
+
+type toolCall struct {
+	Name      string
+	Arguments map[string]any
+}
+
+// readToolCallsContext parses the `toolCalls` array from MCP_CONFORMANCE_CONTEXT.
+// Format: {"toolCalls": [{"name":"...", "arguments":{...}}, ...]}.
+func readToolCallsContext(configCtx map[string]any) []toolCall {
+	raw, ok := configCtx["toolCalls"].([]any)
+	if !ok {
+		return nil
+	}
+	out := make([]toolCall, 0, len(raw))
+	for _, item := range raw {
+		obj, ok := item.(map[string]any)
+		if !ok {
+			continue
+		}
+		name, _ := obj["name"].(string)
+		args, _ := obj["arguments"].(map[string]any)
+		if args == nil {
+			args = map[string]any{}
+		}
+		out = append(out, toolCall{Name: name, Arguments: args})
+	}
+	return out
+}
+
 // ============================================================================
 // Main entry point
 // ============================================================================