diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 384a340..57de58b 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -2569,4 +2569,13 @@ target_link_libraries(step409_test PRIVATE
     tree_sitter_javascript tree_sitter_typescript
     tree_sitter_java tree_sitter_rust tree_sitter_go)
 
+add_executable(step410_test tests/step410_test.cpp)
+target_include_directories(step410_test PRIVATE src)
+target_link_libraries(step410_test PRIVATE
+    nlohmann_json::nlohmann_json
+    unofficial::tree-sitter::tree-sitter
+    tree_sitter_python tree_sitter_cpp tree_sitter_elisp
+    tree_sitter_javascript tree_sitter_typescript
+    tree_sitter_java tree_sitter_rust tree_sitter_go)
+
 # Step 12: Dear ImGui shell scaffolding created (main.cpp exists but not built due to dependencies)
diff --git a/editor/src/CompactAST.h b/editor/src/CompactAST.h
index bc8faae..75d8176 100644
--- a/editor/src/CompactAST.h
+++ b/editor/src/CompactAST.h
@@ -8,6 +8,7 @@
 #include "ast/Serialization.h"
 #include "ast/Annotation.h"
 #include "ast/HostBoundary.h"
+#include "ast/SqlNodes.h"
 #include "ASTUtils.h"
 #include "EnvironmentSpec.h"
 #include <nlohmann/json.hpp>
@@ -431,7 +432,6 @@ inline std::string getNodeName(const ASTNode* node) {
         return static_cast<const PragmaDirective*>(node)->directive;
     if (ct == "MacroDefinition")
         return static_cast<const MacroDefinition*>(node)->name;
-    // Enum/Namespace/TypeAlias (Step 338)
     if (ct == "EnumDeclaration")
         return static_cast<const EnumDeclaration*>(node)->name;
     if (ct == "EnumMember")
@@ -440,6 +440,24 @@ inline std::string getNodeName(const ASTNode* node) {
         return static_cast<const NamespaceDeclaration*>(node)->name;
     if (ct == "TypeAlias")
         return static_cast<const TypeAlias*>(node)->aliasName;
+    if (ct == "TableDeclaration")
+        return static_cast<const TableDeclaration*>(node)->name;
+    if (ct == "ColumnDefinition")
+        return static_cast<const ColumnDefinition*>(node)->name;
+    if (ct == "SelectQuery")
+        return "select";
+    if (ct == "InsertStatement")
+        return static_cast<const InsertStatement*>(node)->tableName;
+    if (ct == "UpdateStatement")
+        return static_cast<const UpdateStatement*>(node)->tableName;
+    if (ct == "DeleteStatement")
+        return static_cast<const DeleteStatement*>(node)->tableName;
+    if (ct == "JoinClause")
+        return static_cast<const JoinClause*>(node)->tableName;
+    if (ct == "WhereClause")
+        return "where";
+    if (ct == "IndexDefinition")
+        return static_cast<const IndexDefinition*>(node)->name;
     return "";
 }
 
diff --git a/editor/src/ast/Serialization.h b/editor/src/ast/Serialization.h
index 0e0d714..2de4d69 100644
--- a/editor/src/ast/Serialization.h
+++ b/editor/src/ast/Serialization.h
@@ -19,6 +19,7 @@
 #include "AsyncNodes.h"
 #include "PreprocessorNodes.h"
 #include "EnumNamespaceNodes.h"
+#include "SqlNodes.h"
 
 using json = nlohmann::json;
 
@@ -546,6 +547,50 @@ inline json propertiesToJson(const ASTNode* node) {
         props["targetType"] = n->targetType;
         if (!n->isUsing) props["isUsing"] = n->isUsing;
     }
+    // SQL nodes (Step 410)
+    else if (ct == "TableDeclaration") {
+        auto* n = static_cast<const TableDeclaration*>(node);
+        if (!n->name.empty()) props["name"] = n->name;
+        if (!n->schema.empty()) props["schema"] = n->schema;
+    }
+    else if (ct == "ColumnDefinition") {
+        auto* n = static_cast<const ColumnDefinition*>(node);
+        if (!n->name.empty()) props["name"] = n->name;
+        if (!n->dataType.empty()) props["dataType"] = n->dataType;
+        props["nullable"] = n->nullable;
+        if (!n->defaultValue.empty()) props["defaultValue"] = n->defaultValue;
+    }
+    else if (ct == "SelectQuery") {
+        auto* n = static_cast<const SelectQuery*>(node);
+        if (n->distinct) props["distinct"] = n->distinct;
+    }
+    else if (ct == "InsertStatement") {
+        auto* n = static_cast<const InsertStatement*>(node);
+        if (!n->tableName.empty()) props["tableName"] = n->tableName;
+    }
+    else if (ct == "UpdateStatement") {
+        auto* n = static_cast<const UpdateStatement*>(node);
+        if (!n->tableName.empty()) props["tableName"] = n->tableName;
+    }
+    else if (ct == "DeleteStatement") {
+        auto* n = static_cast<const DeleteStatement*>(node);
+        if (!n->tableName.empty()) props["tableName"] = n->tableName;
+    }
+    else if (ct == "JoinClause") {
+        auto* n = static_cast<const JoinClause*>(node);
+        if (!n->joinType.empty()) props["joinType"] = n->joinType;
+        if (!n->tableName.empty()) props["tableName"] = n->tableName;
+    }
+    else if (ct == "WhereClause") {
+        auto* n = static_cast<const WhereClause*>(node);
+        if (!n->expression.empty()) props["expression"] = n->expression;
+    }
+    else if (ct == "IndexDefinition") {
+        auto* n = static_cast<const IndexDefinition*>(node);
+        if (!n->name.empty()) props["name"] = n->name;
+        if (!n->tableName.empty()) props["tableName"] = n->tableName;
+        if (n->unique) props["unique"] = n->unique;
+    }
     // NullLiteral, ListLiteral, IndexAccess, Block, Assignment, IfStatement,
     // WhileLoop, Return, ExpressionStatement, ListType, SetType, MapType,
     // TupleType, ArrayType, OptionalType — no extra properties
@@ -716,6 +761,15 @@ inline ASTNode* createNode(const std::string& conceptName) {
     if (conceptName == "EnumMember") return new EnumMember();
     if (conceptName == "NamespaceDeclaration") return new NamespaceDeclaration();
     if (conceptName == "TypeAlias") return new TypeAlias();
+    if (conceptName == "TableDeclaration") return new TableDeclaration();
+    if (conceptName == "ColumnDefinition") return new ColumnDefinition();
+    if (conceptName == "SelectQuery") return new SelectQuery();
+    if (conceptName == "InsertStatement") return new InsertStatement();
+    if (conceptName == "UpdateStatement") return new UpdateStatement();
+    if (conceptName == "DeleteStatement") return new DeleteStatement();
+    if (conceptName == "JoinClause") return new JoinClause();
+    if (conceptName == "WhereClause") return new WhereClause();
+    if (conceptName == "IndexDefinition") return new IndexDefinition();
     return nullptr;
 }
 
@@ -1279,6 +1333,50 @@ inline void setPropertiesFromJson(ASTNode* node, const json& props) {
         if (props.contains("targetType")) n->targetType = props["targetType"].get<std::string>();
         if (props.contains("isUsing")) n->isUsing = props["isUsing"].get<bool>();
     }
+    // SQL nodes (Step 410)
+    else if (ct == "TableDeclaration") {
+        auto* n = static_cast<TableDeclaration*>(node);
+        if (props.contains("name")) n->name = props["name"].get<std::string>();
+        if (props.contains("schema")) n->schema = props["schema"].get<std::string>();
+    }
+    else if (ct == "ColumnDefinition") {
+        auto* n = static_cast<ColumnDefinition*>(node);
+        if (props.contains("name")) n->name = props["name"].get<std::string>();
+        if (props.contains("dataType")) n->dataType = props["dataType"].get<std::string>();
+        if (props.contains("nullable")) n->nullable = props["nullable"].get<bool>();
+        if (props.contains("defaultValue")) n->defaultValue = props["defaultValue"].get<std::string>();
+    }
+    else if (ct == "SelectQuery") {
+        auto* n = static_cast<SelectQuery*>(node);
+        if (props.contains("distinct")) n->distinct = props["distinct"].get<bool>();
+    }
+    else if (ct == "InsertStatement") {
+        auto* n = static_cast<InsertStatement*>(node);
+        if (props.contains("tableName")) n->tableName = props["tableName"].get<std::string>();
+    }
+    else if (ct == "UpdateStatement") {
+        auto* n = static_cast<UpdateStatement*>(node);
+        if (props.contains("tableName")) n->tableName = props["tableName"].get<std::string>();
+    }
+    else if (ct == "DeleteStatement") {
+        auto* n = static_cast<DeleteStatement*>(node);
+        if (props.contains("tableName")) n->tableName = props["tableName"].get<std::string>();
+    }
+    else if (ct == "JoinClause") {
+        auto* n = static_cast<JoinClause*>(node);
+        if (props.contains("joinType")) n->joinType = props["joinType"].get<std::string>();
+        if (props.contains("tableName")) n->tableName = props["tableName"].get<std::string>();
+    }
+    else if (ct == "WhereClause") {
+        auto* n = static_cast<WhereClause*>(node);
+        if (props.contains("expression")) n->expression = props["expression"].get<std::string>();
+    }
+    else if (ct == "IndexDefinition") {
+        auto* n = static_cast<IndexDefinition*>(node);
+        if (props.contains("name")) n->name = props["name"].get<std::string>();
+        if (props.contains("tableName")) n->tableName = props["tableName"].get<std::string>();
+        if (props.contains("unique")) n->unique = props["unique"].get<bool>();
+    }
 }
 
 inline std::string generateNodeId() {
diff --git a/editor/src/ast/SqlNodes.h b/editor/src/ast/SqlNodes.h
new file mode 100644
index 0000000..c1e443f
--- /dev/null
+++ b/editor/src/ast/SqlNodes.h
@@ -0,0 +1,112 @@
+#pragma once
+
+#include "ASTNode.h"
+#include <string>
+
+// SQL-specific AST nodes (Step 410)
+
+class TableDeclaration : public ASTNode {
+public:
+    std::string name;
+    std::string schema;
+    TableDeclaration() { conceptType = "TableDeclaration"; }
+    TableDeclaration(const std::string& id_, const std::string& n, const std::string& s = "")
+        : name(n), schema(s) {
+        id = id_;
+        conceptType = "TableDeclaration";
+    }
+    // children: "columns" (ColumnDefinition), "indexes" (IndexDefinition)
+};
+
+class ColumnDefinition : public ASTNode {
+public:
+    std::string name;
+    std::string dataType;
+    bool nullable = true;
+    std::string defaultValue;
+    ColumnDefinition() { conceptType = "ColumnDefinition"; }
+    ColumnDefinition(const std::string& id_, const std::string& n,
+                     const std::string& dt, bool isNullable = true)
+        : name(n), dataType(dt), nullable(isNullable) {
+        id = id_;
+        conceptType = "ColumnDefinition";
+    }
+};
+
+class SelectQuery : public ASTNode {
+public:
+    bool distinct = false;
+    SelectQuery() { conceptType = "SelectQuery"; }
+    // children: "columns", "from", "joins", "where"
+};
+
+class InsertStatement : public ASTNode {
+public:
+    std::string tableName;
+    InsertStatement() { conceptType = "InsertStatement"; }
+    InsertStatement(const std::string& id_, const std::string& table) : tableName(table) {
+        id = id_;
+        conceptType = "InsertStatement";
+    }
+    // children: "columns", "values"
+};
+
+class UpdateStatement : public ASTNode {
+public:
+    std::string tableName;
+    UpdateStatement() { conceptType = "UpdateStatement"; }
+    UpdateStatement(const std::string& id_, const std::string& table) : tableName(table) {
+        id = id_;
+        conceptType = "UpdateStatement";
+    }
+    // children: "set", "where"
+};
+
+class DeleteStatement : public ASTNode {
+public:
+    std::string tableName;
+    DeleteStatement() { conceptType = "DeleteStatement"; }
+    DeleteStatement(const std::string& id_, const std::string& table) : tableName(table) {
+        id = id_;
+        conceptType = "DeleteStatement";
+    }
+    // children: "where"
+};
+
+class JoinClause : public ASTNode {
+public:
+    std::string joinType;   // INNER/LEFT/RIGHT/FULL
+    std::string tableName;
+    JoinClause() { conceptType = "JoinClause"; }
+    JoinClause(const std::string& id_, const std::string& jt, const std::string& tn)
+        : joinType(jt), tableName(tn) {
+        id = id_;
+        conceptType = "JoinClause";
+    }
+    // children: "on"
+};
+
+class WhereClause : public ASTNode {
+public:
+    std::string expression;
+    WhereClause() { conceptType = "WhereClause"; }
+    WhereClause(const std::string& id_, const std::string& expr) : expression(expr) {
+        id = id_;
+        conceptType = "WhereClause";
+    }
+};
+
+class IndexDefinition : public ASTNode {
+public:
+    std::string name;
+    std::string tableName;
+    bool unique = false;
+    IndexDefinition() { conceptType = "IndexDefinition"; }
+    IndexDefinition(const std::string& id_, const std::string& n,
+                    const std::string& table, bool isUnique = false)
+        : name(n), tableName(table), unique(isUnique) {
+        id = id_;
+        conceptType = "IndexDefinition";
+    }
+    // children: "columns"
+};
diff --git a/editor/tests/step410_test.cpp b/editor/tests/step410_test.cpp
new file mode 100644
index 0000000..b513386
--- /dev/null
+++ b/editor/tests/step410_test.cpp
@@ -0,0 +1,202 @@
+// Step 410: SQL AST Nodes (12 tests)
+// Tests construction + serialization roundtrip for SQL-specific node types.
+
+#include <cassert>
+#include <iostream>
+
+#include "ast/SqlNodes.h"
+#include "ast/Serialization.h"
+#include "CompactAST.h"
+
+int main() {
+    int passed = 0;
+
+    // 1. TableDeclaration construction
+    {
+        auto* t = new TableDeclaration("t1", "users", "public");
+        assert(t->conceptType == "TableDeclaration");
+        assert(t->name == "users");
+        assert(t->schema == "public");
+        delete t;
+        std::cout << "Test 1 PASSED: TableDeclaration construction\n";
+        passed++;
+    }
+
+    // 2. ColumnDefinition construction
+    {
+        auto* c = new ColumnDefinition("c1", "id", "INTEGER", false);
+        c->defaultValue = "0";
+        assert(c->conceptType == "ColumnDefinition");
+        assert(c->name == "id");
+        assert(c->dataType == "INTEGER");
+        assert(!c->nullable);
+        assert(c->defaultValue == "0");
+        delete c;
+        std::cout << "Test 2 PASSED: ColumnDefinition construction\n";
+        passed++;
+    }
+
+    // 3. SelectQuery + clauses children
+    {
+        auto* q = new SelectQuery();
+        q->id = "q1";
+        q->distinct = true;
+        q->addChild("joins", new JoinClause("j1", "INNER", "orders"));
+        q->setChild("where", new WhereClause("w1", "id > 10"));
+        assert(q->distinct);
+        assert(q->getChildren("joins").size() == 1);
+        assert(q->getChild("where") != nullptr);
+        delete q;
+        std::cout << "Test 3 PASSED: SelectQuery with clauses\n";
+        passed++;
+    }
+
+    // 4. InsertStatement construction
+    {
+        auto* ins = new InsertStatement("i1", "users");
+        ins->addChild("columns", new ColumnDefinition("c2", "name", "TEXT"));
+        assert(ins->conceptType == "InsertStatement");
+        assert(ins->tableName == "users");
+        assert(ins->getChildren("columns").size() == 1);
+        delete ins;
+        std::cout << "Test 4 PASSED: InsertStatement construction\n";
+        passed++;
+    }
+
+    // 5. UpdateStatement construction
+    {
+        auto* up = new UpdateStatement("u1", "users");
+        up->setChild("where", new WhereClause("w2", "id = 1"));
+        assert(up->conceptType == "UpdateStatement");
+        assert(up->tableName == "users");
+        assert(up->getChild("where") != nullptr);
+        delete up;
+        std::cout << "Test 5 PASSED: UpdateStatement construction\n";
+        passed++;
+    }
+
+    // 6. DeleteStatement construction
+    {
+        auto* del = new DeleteStatement("d1", "logs");
+        del->setChild("where", new WhereClause("w3", "created_at < now()"));
+        assert(del->conceptType == "DeleteStatement");
+        assert(del->tableName == "logs");
+        assert(del->getChild("where") != nullptr);
+        delete del;
+        std::cout << "Test 6 PASSED: DeleteStatement construction\n";
+        passed++;
+    }
+
+    // 7. IndexDefinition construction
+    {
+        auto* idx = new IndexDefinition("x1", "idx_users_email", "users", true);
+        idx->addChild("columns", new ColumnDefinition("c3", "email", "TEXT"));
+        assert(idx->conceptType == "IndexDefinition");
+        assert(idx->name == "idx_users_email");
+        assert(idx->tableName == "users");
+        assert(idx->unique);
+        delete idx;
+        std::cout << "Test 7 PASSED: IndexDefinition construction\n";
+        passed++;
+    }
+
+    // 8. Table with columns + index JSON roundtrip
+    {
+        auto* t = new TableDeclaration("t2", "accounts", "public");
+        t->addChild("columns", new ColumnDefinition("c4", "id", "BIGINT", false));
+        t->addChild("columns", new ColumnDefinition("c5", "email", "TEXT", false));
+        t->addChild("indexes", new IndexDefinition("x2", "idx_accounts_email", "accounts", true));
+        json j = toJson(t);
+        auto* r = fromJson(j);
+        assert(r->conceptType == "TableDeclaration");
+        auto* rt = static_cast<TableDeclaration*>(r);
+        assert(rt->name == "accounts");
+        assert(rt->getChildren("columns").size() == 2);
+        assert(rt->getChildren("indexes").size() == 1);
+        delete t;
+        delete r;
+        std::cout << "Test 8 PASSED: table JSON roundtrip\n";
+        passed++;
+    }
+
+    // 9. SelectQuery JSON roundtrip
+    {
+        auto* q = new SelectQuery();
+        q->id = "q2";
+        q->distinct = true;
+        q->addChild("joins", new JoinClause("j2", "LEFT", "profiles"));
+        q->setChild("where", new WhereClause("w4", "active = true"));
+        json j = toJson(q);
+        auto* r = fromJson(j);
+        assert(r->conceptType == "SelectQuery");
+        auto* rq = static_cast<SelectQuery*>(r);
+        assert(rq->distinct);
+        assert(rq->getChildren("joins").size() == 1);
+        assert(rq->getChild("where") != nullptr);
+        delete q;
+        delete r;
+        std::cout << "Test 9 PASSED: select JSON roundtrip\n";
+        passed++;
+    }
+
+    // 10. CompactAST names
+    {
+        auto* t = new TableDeclaration("t3", "sessions");
+        auto* c = new ColumnDefinition("c6", "token", "TEXT");
+        auto* q = new SelectQuery();
+        q->id = "q3";
+        auto* d = new DeleteStatement("d2", "sessions");
+        auto* w = new WhereClause("w5", "expired = true");
+        auto* x = new IndexDefinition("x3", "idx_sessions_token", "sessions");
+        assert(getNodeName(t) == "sessions");
+        assert(getNodeName(c) == "token");
+        assert(getNodeName(q) == "select");
+        assert(getNodeName(d) == "sessions");
+        assert(getNodeName(w) == "where");
+        assert(getNodeName(x) == "idx_sessions_token");
+        delete t; delete c; delete q; delete d; delete w; delete x;
+        std::cout << "Test 10 PASSED: CompactAST SQL names\n";
+        passed++;
+    }
+
+    // 11. createNode dispatch for SQL concepts
+    {
+        ASTNode* t = createNode("TableDeclaration");
+        ASTNode* c = createNode("ColumnDefinition");
+        ASTNode* s = createNode("SelectQuery");
+        ASTNode* i = createNode("InsertStatement");
+        ASTNode* u = createNode("UpdateStatement");
+        ASTNode* d = createNode("DeleteStatement");
+        ASTNode* j = createNode("JoinClause");
+        ASTNode* w = createNode("WhereClause");
+        ASTNode* x = createNode("IndexDefinition");
+        assert(t && c && s && i && u && d && j && w && x);
+        delete t; delete c; delete s; delete i; delete u; delete d; delete j; delete w; delete x;
+        std::cout << "Test 11 PASSED: createNode SQL dispatch\n";
+        passed++;
+    }
+
+    // 12. Full query graph roundtrip
+    {
+        auto* q = new SelectQuery();
+        q->id = "q4";
+        q->addChild("columns", new ColumnDefinition("c7", "id", "INTEGER"));
+        q->setChild("from", new TableDeclaration("t4", "users"));
+        q->addChild("joins", new JoinClause("j3", "INNER", "orders"));
+        q->setChild("where", new WhereClause("w6", "users.id = orders.user_id"));
+        json j = toJson(q);
+        auto* r = fromJson(j);
+        assert(r->conceptType == "SelectQuery");
+        assert(r->getChildren("columns").size() == 1);
+        assert(r->getChild("from") != nullptr);
+        assert(r->getChildren("joins").size() == 1);
+        assert(r->getChild("where") != nullptr);
+        delete q;
+        delete r;
+        std::cout << "Test 12 PASSED: full query graph roundtrip\n";
+        passed++;
+    }
+
+    std::cout << "\nResults: " << passed << "/12 tests passed\n";
+    return (passed == 12) ? 0 : 1;
+}
diff --git a/progress.md b/progress.md
index 1433100..c370319 100644
--- a/progress.md
+++ b/progress.md
@@ -3861,6 +3861,60 @@ Semanno annotation behavior across all 3 .NET-targeted outputs.
   - `editor/src/MCPServer.h` (`1679` > `600`)
   - `editor/src/HeadlessAgentRPCHandler.h` (`2623` > `600`)
 
+## Phase 17b: SQL Dialect Support
+
+### Step 410: SQL AST Nodes
+**Status:** PASS (12/12 tests)
+
+Added first-class SQL AST node types and wired JSON serialization/deserialization
+and compact-node naming support so SQL structures can participate in existing
+pipeline tooling.
+
+**Files created:**
+- `editor/src/ast/SqlNodes.h` — SQL node definitions:
+  - `TableDeclaration`
+  - `ColumnDefinition`
+  - `SelectQuery`
+  - `InsertStatement`
+  - `UpdateStatement`
+  - `DeleteStatement`
+  - `JoinClause`
+  - `WhereClause`
+  - `IndexDefinition`
+- `editor/tests/step410_test.cpp` — 12 tests covering:
+  1. table construction
+  2. column construction
+  3. select query + clause children
+  4. insert statement construction
+  5. update statement construction
+  6. delete statement construction
+  7. index construction
+  8. table+columns+index JSON roundtrip
+  9. select query JSON roundtrip
+  10. compact AST naming for SQL nodes
+  11. `createNode` SQL concept dispatch
+  12. full query graph roundtrip
+
+**Files modified:**
+- `editor/src/ast/Serialization.h` — SQL node property serialization,
+  `createNode` mapping, and deserialization
+- `editor/src/CompactAST.h` — SQL node name mapping in `getNodeName`
+- `editor/CMakeLists.txt` — `step410_test` target
+
+**Verification run:**
+- `step410_test` — PASS (12/12) new step coverage
+- `step409_test` — PASS (8/8) regression coverage
+- `step408_test` — PASS (12/12) regression coverage
+
+**Architecture gate check:**
+- `editor/src/ast/SqlNodes.h` within header-size limit (`112` <= `600`)
+- `editor/tests/step410_test.cpp` within test-file size guidance (`202` lines)
+- `editor/src/CompactAST.h` at header-size limit (`600` <= `600`)
+- Legacy oversized headers persist:
+  - `editor/src/ast/Serialization.h` (`1427` > `600`)
+  - `editor/src/MCPServer.h` (`1679` > `600`)
+  - `editor/src/HeadlessAgentRPCHandler.h` (`2623` > `600`)
+
 # Roadmap Planning — Sprints 12-25+
 
 ## Status: Planning Complete (Sprints 12-19 detailed, 20-25 in roadmap.md)