feat(pgsql): support vector and PostGIS indexes with extensions

* Add handling for pgvector and PostGIS extensions in migration scripts
* Implement operator class and storage parameters for vector indexes
* Update tests to validate new index behaviors and extension creation

pkg/writers/pgsql/README.md

@@ -171,6 +171,7 @@ When `include_audit` is enabled, adds:
 - Function-based indexes
 - Concurrent index creation (`CREATE INDEX CONCURRENTLY`) via `Index.Concurrent`
 - Check constraints with expressions
+- Extension types and indexes: PostGIS, pgvector, citext, hstore, ltree (see below)
 
 ## Data Types
 
@@ -186,6 +187,108 @@ Supports all PostgreSQL data types:
 - Network: INET, CIDR, MACADDR
 - Special: ARRAY, HSTORE
 
+## Extension Types (PostGIS, pgvector)
+
+Extension column types are preserved verbatim, including their type modifier:
+
+| Type | Example column type | Extension |
+|------|---------------------|-----------|
+| PostGIS | `geometry(Point,4326)`, `geography(Point)`, `box2d`, `raster` | `postgis`, `postgis_raster`, `postgis_topology` |
+| pgvector | `vector(1536)`, `halfvec(768)`, `sparsevec(1000)` | `vector` |
+| Other | `citext`, `hstore`, `ltree` | `citext`, `hstore`, `ltree` |
+
+`CREATE EXTENSION IF NOT EXISTS <ext>;` is emitted automatically for every extension the
+schema needs. See [Extensions](#extensions).
+
+### Extension Indexes
+
+`Index.Type` selects the access method: `gist`, `spgist`, `brin` (PostGIS), `hnsw`, `ivfflat`
+(pgvector), `vchordrq`, `vchordg` (VectorChord), `bm25` (pg_search).
+
+Operator class and access-method parameters ride in `Index.Comment`:
+
+```
+opclass=vector_l2_ops; with (lists=100)
+```
+
+- `opclass=<name>` — used only when compatible with the column type; otherwise ignored.
+  Bare operator class names in the comment (e.g. `gin_trgm_ops`) are also recognized.
+- `with (k=v, …)` — rendered as `WITH (k = v, …)`. Only well-formed `key = value` pairs are
+  kept, so comment prose never reaches the DDL. Values may be bare (`lists=100`), quoted
+  (`key_field='id'`), or dollar-quoted (`options=$$[build.internal]$$`).
+
+Defaults when no operator class is requested:
+
+| Access method | Column type | Emitted operator class |
+|---------------|-------------|------------------------|
+| `hnsw`, `ivfflat`, `vchordrq`, `vchordg` | `vector` / `halfvec` / `sparsevec` / `bit` | `vector_cosine_ops` / `halfvec_cosine_ops` / `sparsevec_cosine_ops` / `bit_hamming_ops` |
+| `gist`, `spgist`, `brin` | `geometry`, `geography` | none (PostGIS default operator class) |
+| `gin` | text / `jsonb` / array | `gin_trgm_ops` / `jsonb_ops` / `array_ops` |
+
+pgvector defines no default operator class, so a vector index always names one.
+
+```sql
+CREATE INDEX IF NOT EXISTS idx_documents_embedding
+  ON public.documents USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100);
+CREATE INDEX IF NOT EXISTS idx_documents_location
+  ON public.documents USING gist (location);
+```
+
+Migrations only recreate an index when both sides specify a hint and they differ, so a model
+without hints does not churn against a live database.
+
+## Extensions
+
+`CREATE EXTENSION IF NOT EXISTS <ext>;` is emitted per schema, deduplicated and ordered so
+dependencies come first (`postgis` before `postgis_topology`/`postgis_raster`/`pgrouting`,
+`vector` before `vchord`). Names needing quoting are quoted: `CREATE EXTENSION IF NOT EXISTS "uuid-ossp";`
+
+### Detection
+
+| Source | Example | Extension |
+|--------|---------|-----------|
+| Column type | `vector(1536)`, `geometry(Point,4326)`, `citext`, `ltree` | `vector`, `postgis`, `citext`, `ltree` |
+| Index access method | `hnsw`, `ivfflat` / `vchordrq`, `vchordg` / `bm25` | `vector` / `vchord` / `pg_search` |
+| Operator class | `gin_trgm_ops`, `gist_ltree_ops` | `pg_trgm`, `ltree` |
+| GIN/GiST on a scalar type | `USING gin (views)` | `btree_gin` / `btree_gist` |
+| Function in a default, CHECK, index `WHERE`, or view body | `uuid_generate_v4()`, `crypt()`, `ST_Area()`, `unaccent()`, `json_matches_schema()` | `uuid-ossp`, `pgcrypto`, `postgis`, `unaccent`, `pg_jsonschema` |
+
+`gen_random_uuid()` is built in since PostgreSQL 13 and does not pull in `pgcrypto`.
+
+### Declaring extensions explicitly
+
+Extensions that leave no trace in the schema go in `schema.Metadata["extensions"]`, as a list
+or a comma-separated string. Dependencies are pulled in automatically; unknown names are kept
+as given. The PostgreSQL reader populates this from `pg_extension` for the schemas it reads.
+
+```yaml
+metadata:
+  extensions: [pg_cron, timescaledb, pg_stat_statements]
+```
+
+### Recognized extensions
+
+| Category | Extensions |
+|----------|------------|
+| ai/search | `vector`, `vchord` |
+| document | `hstore`, `ltree` |
+| federation | `postgres_fdw` |
+| geospatial | `postgis`, `postgis_raster`, `postgis_topology`, `pgrouting` |
+| indexing | `btree_gin`, `btree_gist` |
+| integration | `http` |
+| integrity | `amcheck` |
+| jobs / scheduling | `pg_background`, `pg_cron` |
+| maintenance | `pg_repack`, `pgstattuple` |
+| observability | `pg_qualstats`, `pg_stat_statements` |
+| partitioning | `pg_partman` |
+| procedural | `plpython3u` |
+| search | `pg_search`, `pg_textsearch` |
+| security | `pgcrypto` |
+| text | `citext`, `fuzzystrmatch`, `pg_trgm`, `unaccent` |
+| time-series | `timescaledb` |
+| utility | `uuid-ossp` |
+| validation | `pg_jsonschema` |
+
 ## Notes
 
 - Generated SQL is formatted and readable

pkg/writers/pgsql/extensions_test.go

@@ -0,0 +1,260 @@
+package pgsql
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
+)
+
+// buildExtensionSchema returns a single-table schema the extension detection tests mutate.
+func buildExtensionSchema(t *testing.T) (*models.Schema, *models.Table) {
+	t.Helper()
+
+	schema := models.InitSchema("public")
+	table := models.InitTable("documents", "public")
+	schema.Tables = append(schema.Tables, table)
+	return schema, table
+}
+
+func addColumn(table *models.Table, name, sqlType string) *models.Column {
+	col := models.InitColumn(name, table.Name, table.Schema)
+	col.Type = sqlType
+	table.Columns[name] = col
+	return col
+}
+
+func TestRequiredExtensions_Detection(t *testing.T) {
+	tests := []struct {
+		name  string
+		build func(schema *models.Schema, table *models.Table)
+		want  []string
+	}{
+		{
+			name:  "no extensions",
+			build: func(_ *models.Schema, table *models.Table) { addColumn(table, "id", "integer") },
+			want:  nil,
+		},
+		{
+			name: "column type",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "embedding", "vector(1536)")
+				addColumn(table, "name", "citext")
+			},
+			want: []string{"citext", "vector"},
+		},
+		{
+			name: "column default function",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "id", "uuid").Default = "uuid_generate_v4()"
+			},
+			want: []string{"uuid-ossp"},
+		},
+		{
+			name: "check constraint expression",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "geom", "geometry")
+				table.Constraints["chk_geom"] = &models.Constraint{
+					Name:       "chk_geom",
+					Type:       models.CheckConstraint,
+					Expression: "ST_IsValid(geom)",
+				}
+			},
+			want: []string{"postgis"},
+		},
+		{
+			name: "partial index predicate",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "title", "text")
+				table.Indexes["idx_title"] = &models.Index{
+					Name:    "idx_title",
+					Type:    "btree",
+					Columns: []string{"title"},
+					Where:   "similarity(title, 'x') > 0.3",
+				}
+			},
+			want: []string{"pg_trgm"},
+		},
+		{
+			name: "view definition",
+			build: func(schema *models.Schema, table *models.Table) {
+				addColumn(table, "title", "text")
+				schema.Views = append(schema.Views, &models.View{
+					Name:       "v_documents",
+					Schema:     "public",
+					Definition: "SELECT unaccent(title) FROM documents",
+				})
+			},
+			want: []string{"unaccent"},
+		},
+		{
+			name: "index access method",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "body", "text")
+				table.Indexes["idx_body"] = &models.Index{
+					Name:    "idx_body",
+					Type:    "bm25",
+					Columns: []string{"body"},
+					Comment: "with (key_field='id')",
+				}
+			},
+			want: []string{"pg_search"},
+		},
+		{
+			name: "vchord depends on vector",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "embedding", "vector(3)")
+				table.Indexes["idx_embedding"] = &models.Index{
+					Name:    "idx_embedding",
+					Type:    "vchordrq",
+					Columns: []string{"embedding"},
+				}
+			},
+			want: []string{"vector", "vchord"},
+		},
+		{
+			name: "gin on scalar needs btree_gin",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "views", "integer")
+				table.Indexes["idx_views"] = &models.Index{
+					Name:    "idx_views",
+					Type:    "gin",
+					Columns: []string{"views"},
+				}
+			},
+			want: []string{"btree_gin"},
+		},
+		{
+			name: "gist on scalar needs btree_gist",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "views", "integer")
+				table.Indexes["idx_views"] = &models.Index{
+					Name:    "idx_views",
+					Type:    "gist",
+					Columns: []string{"views"},
+				}
+			},
+			want: []string{"btree_gist"},
+		},
+		{
+			name: "gist on geometry uses postgis operator classes",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "location", "geometry(Point,4326)")
+				table.Indexes["idx_location"] = &models.Index{
+					Name:    "idx_location",
+					Type:    "gist",
+					Columns: []string{"location"},
+				}
+			},
+			want: []string{"postgis"},
+		},
+		{
+			name: "gin on jsonb needs no companion",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "payload", "jsonb")
+				table.Indexes["idx_payload"] = &models.Index{
+					Name:    "idx_payload",
+					Type:    "gin",
+					Columns: []string{"payload"},
+				}
+			},
+			want: nil,
+		},
+		{
+			name: "gin on text uses pg_trgm",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "title", "text")
+				table.Indexes["idx_title"] = &models.Index{
+					Name:    "idx_title",
+					Type:    "gin",
+					Columns: []string{"title"},
+				}
+			},
+			want: []string{"pg_trgm"},
+		},
+		{
+			name: "gin on array needs no companion",
+			build: func(_ *models.Schema, table *models.Table) {
+				addColumn(table, "tags", "text[]")
+				table.Indexes["idx_tags"] = &models.Index{
+					Name:    "idx_tags",
+					Type:    "gin",
+					Columns: []string{"tags"},
+				}
+			},
+			want: nil,
+		},
+		{
+			name: "declared in metadata as string",
+			build: func(schema *models.Schema, _ *models.Table) {
+				schema.Metadata = map[string]any{"extensions": "pg_cron, timescaledb"}
+			},
+			want: []string{"pg_cron", "timescaledb"},
+		},
+		{
+			name: "declared in metadata as list",
+			build: func(schema *models.Schema, _ *models.Table) {
+				schema.Metadata = map[string]any{"extensions": []any{"postgis_topology", "pg_stat_statements"}}
+			},
+			// postgis is pulled in as a dependency of postgis_topology and emitted first.
+			want: []string{"pg_stat_statements", "postgis", "postgis_topology"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			schema, table := buildExtensionSchema(t)
+			tt.build(schema, table)
+
+			if got := requiredExtensions(schema); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("requiredExtensions() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRequiredExtensions_NilSchema(t *testing.T) {
+	if got := requiredExtensions(nil); got != nil {
+		t.Errorf("requiredExtensions(nil) = %v, want nil", got)
+	}
+}
+
+func TestWriteDatabase_QuotesExtensionNames(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema, table := buildExtensionSchema(t)
+	addColumn(table, "id", "uuid").Default = "uuid_generate_v4()"
+	db.Schemas = append(db.Schemas, schema)
+
+	output := writeDatabaseOutput(t, db)
+	if !strings.Contains(output, `CREATE EXTENSION IF NOT EXISTS "uuid-ossp";`) {
+		t.Fatalf("expected quoted extension name, got:\n%s", output)
+	}
+}
+
+func TestGenerateSchemaStatements_ExtensionDependencyOrder(t *testing.T) {
+	schema, table := buildExtensionSchema(t)
+	addColumn(table, "embedding", "vector(3)")
+	table.Indexes["idx_embedding"] = &models.Index{
+		Name:    "idx_embedding",
+		Type:    "vchordrq",
+		Columns: []string{"embedding"},
+	}
+
+	writer := NewWriter(&writers.WriterOptions{})
+	statements, err := writer.GenerateSchemaStatements(schema)
+	if err != nil {
+		t.Fatalf("GenerateSchemaStatements failed: %v", err)
+	}
+
+	joined := strings.Join(statements, "\n")
+	vector := strings.Index(joined, "CREATE EXTENSION IF NOT EXISTS vector")
+	vchord := strings.Index(joined, "CREATE EXTENSION IF NOT EXISTS vchord")
+	if vector < 0 || vchord < 0 {
+		t.Fatalf("expected vector and vchord extensions, got:\n%s", joined)
+	}
+	if vector > vchord {
+		t.Fatalf("expected vector to be created before vchord, got:\n%s", joined)
+	}
+}

pkg/writers/pgsql/migration_writer.go

@@ -164,14 +164,14 @@ func (w *MigrationWriter) WriteMigration(model *models.Database, current *models
 func (w *MigrationWriter) generateSchemaScripts(model *models.Schema, current *models.Schema) ([]MigrationScript, error) {
 	scripts := make([]MigrationScript, 0)
 
-	if schemaRequiresPGTrgm(model) {
+	for _, extension := range requiredExtensions(model) {
 		scripts = append(scripts, MigrationScript{
-			ObjectName: "extension.pg_trgm",
+			ObjectName: "extension." + extension,
 			ObjectType: "create extension",
 			Schema:     model.Name,
 			Priority:   80,
 			Sequence:   len(scripts),
-			Body:       "CREATE EXTENSION IF NOT EXISTS pg_trgm;",
+			Body:       fmt.Sprintf("CREATE EXTENSION IF NOT EXISTS %s;", pgsql.QuoteExtensionName(extension)),
 		})
 	}
 
@@ -646,13 +646,14 @@ func (w *MigrationWriter) generateIndexScripts(model *models.Schema, current *mo
 				}
 
 				sql, err := w.executor.ExecuteCreateIndex(CreateIndexData{
-					SchemaName: model.Name,
-					TableName:  modelTable.Name,
-					IndexName:  indexName,
-					IndexType:  indexType,
-					Columns:    strings.Join(columnExprs, ", "),
-					Unique:     modelIndex.Unique,
-					Concurrent: modelIndex.Concurrent,
+					SchemaName:        model.Name,
+					TableName:         modelTable.Name,
+					IndexName:         indexName,
+					IndexType:         indexType,
+					Columns:           strings.Join(columnExprs, ", "),
+					Unique:            modelIndex.Unique,
+					Concurrent:        modelIndex.Concurrent,
+					StorageParameters: indexStorageParameters(modelIndex.Comment),
 				})
 				if err != nil {
 					return nil, err
@@ -674,20 +675,31 @@ func (w *MigrationWriter) generateIndexScripts(model *models.Schema, current *mo
 	return scripts, nil
 }
 
+// buildIndexColumnExpressions renders the column list of an index, appending the operator
+// class each column needs for the access method (GIN opclasses, pgvector distance ops,
+// explicitly requested PostGIS opclasses). Columns that cannot be resolved on the table are
+// emitted verbatim.
 func buildIndexColumnExpressions(table *models.Table, index *models.Index, indexType string) []string {
+	return buildIndexColumnExpressionsFiltered(table, index, indexType, false)
+}
+
+// buildIndexColumnExpressionsFiltered is buildIndexColumnExpressions with the option to drop
+// columns that do not exist on the table instead of emitting them verbatim.
+func buildIndexColumnExpressionsFiltered(table *models.Table, index *models.Index, indexType string, skipUnresolved bool) []string {
 	columnExprs := make([]string, 0, len(index.Columns))
 	for _, colName := range index.Columns {
-		colExpr := colName
-		if table != nil {
-			if col, ok := resolveIndexColumn(table, colName); ok && col != nil {
-				colExpr = col.SQLName()
-				if strings.EqualFold(indexType, "gin") {
-					opClass := ginOperatorClassForColumn(col, index.Comment)
-					if opClass != "" {
-						colExpr = fmt.Sprintf("%s %s", col.SQLName(), opClass)
-					}
-				}
+		col, ok := resolveIndexColumn(table, colName)
+		if !ok || col == nil {
+			if skipUnresolved {
+				continue
 			}
+			columnExprs = append(columnExprs, colName)
+			continue
+		}
+
+		colExpr := col.SQLName()
+		if opClass := indexOperatorClassForColumn(col, indexType, index.Comment); opClass != "" {
+			colExpr = fmt.Sprintf("%s %s", colExpr, opClass)
 		}
 		columnExprs = append(columnExprs, colExpr)
 	}
@@ -1046,5 +1058,19 @@ func indexesEqual(idx1, idx2 *models.Index) bool {
 			return false
 		}
 	}
-	return true
+	// Operator class and storage parameters ride along in the index comment. They only
+	// signal a difference when both sides specify one, so an index whose model side omits
+	// the hint is not recreated on every migration.
+	if !indexHintsEqual(extractOperatorClass(idx1.Comment), extractOperatorClass(idx2.Comment)) {
+		return false
+	}
+	return indexHintsEqual(indexStorageParameters(idx1.Comment), indexStorageParameters(idx2.Comment))
+}
+
+// indexHintsEqual compares two optional index hints, treating an unspecified hint as a match.
+func indexHintsEqual(hint1, hint2 string) bool {
+	if hint1 == "" || hint2 == "" {
+		return true
+	}
+	return strings.EqualFold(hint1, hint2)
 }

pkg/writers/pgsql/migration_writer_test.go

@@ -852,3 +852,93 @@ func TestWriteMigration_NilCurrentTreatsDatabaseAsEmpty(t *testing.T) {
 		t.Fatalf("expected CREATE TABLE in migration output, got:\n%s", output)
 	}
 }
+
+func TestWriteMigration_VectorAndPostGISIndexes(t *testing.T) {
+	current := models.InitDatabase("testdb")
+	current.Schemas = append(current.Schemas, models.InitSchema("public"))
+
+	model := models.InitDatabase("testdb")
+	modelSchema := models.InitSchema("public")
+
+	table := models.InitTable("documents", "public")
+
+	embedding := models.InitColumn("embedding", "documents", "public")
+	embedding.Type = "vector(1536)"
+	table.Columns["embedding"] = embedding
+
+	location := models.InitColumn("location", "documents", "public")
+	location.Type = "geometry(Point,4326)"
+	table.Columns["location"] = location
+
+	table.Indexes["idx_documents_embedding"] = &models.Index{
+		Name:    "idx_documents_embedding",
+		Type:    "ivfflat",
+		Columns: []string{"embedding"},
+		Comment: "opclass=vector_cosine_ops; with (lists=100)",
+	}
+	table.Indexes["idx_documents_location"] = &models.Index{
+		Name:    "idx_documents_location",
+		Type:    "gist",
+		Columns: []string{"location"},
+	}
+
+	modelSchema.Tables = append(modelSchema.Tables, table)
+	model.Schemas = append(model.Schemas, modelSchema)
+
+	var buf bytes.Buffer
+	writer, err := NewMigrationWriter(&writers.WriterOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create writer: %v", err)
+	}
+	writer.writer = &buf
+
+	if err := writer.WriteMigration(model, current); err != nil {
+		t.Fatalf("WriteMigration failed: %v", err)
+	}
+
+	output := buf.String()
+	for _, want := range []string{
+		"CREATE EXTENSION IF NOT EXISTS postgis;",
+		"CREATE EXTENSION IF NOT EXISTS vector;",
+		"vector(1536)",
+		"geometry(Point,4326)",
+		"USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100)",
+		"USING gist (location)",
+	} {
+		if !strings.Contains(output, want) {
+			t.Fatalf("expected migration to contain %q, got:\n%s", want, output)
+		}
+	}
+}
+
+func TestIndexesEqual_OperatorClassAndStorageParameters(t *testing.T) {
+	newIndex := func(comment string) *models.Index {
+		return &models.Index{
+			Name:    "idx_documents_embedding",
+			Type:    "hnsw",
+			Columns: []string{"embedding"},
+			Comment: comment,
+		}
+	}
+
+	tests := []struct {
+		name      string
+		comment1  string
+		comment2  string
+		wantEqual bool
+	}{
+		{"identical hints", "opclass=vector_l2_ops", "opclass=vector_l2_ops", true},
+		{"different operator class", "opclass=vector_l2_ops", "opclass=vector_cosine_ops", false},
+		{"different storage parameters", "with (m=16)", "with (m=32)", false},
+		{"unspecified hint on one side", "", "opclass=vector_l2_ops; with (m=16)", true},
+		{"unrelated comments", "primary lookup index", "primary lookup index", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := indexesEqual(newIndex(tt.comment1), newIndex(tt.comment2)); got != tt.wantEqual {
+				t.Errorf("indexesEqual() = %v, want %v", got, tt.wantEqual)
+			}
+		})
+	}
+}

pkg/writers/pgsql/templates.go

@@ -140,6 +140,9 @@ type CreateIndexData struct {
 	Columns    string
 	Unique     bool
 	Concurrent bool
+	// StorageParameters holds access-method parameters rendered as WITH (...),
+	// e.g. "lists = 100" for ivfflat or "m = 16, ef_construction = 64" for hnsw.
+	StorageParameters string
 }
 
 // CreateForeignKeyData contains data for create foreign key template

pkg/writers/pgsql/templates/create_index.tmpl

@@ -1,2 +1,2 @@
 CREATE {{if .Unique}}UNIQUE {{end}}INDEX {{if .Concurrent}}CONCURRENTLY {{end}}IF NOT EXISTS {{quote_ident .IndexName}}
-  ON {{qual_table .SchemaName .TableName}} USING {{.IndexType}} ({{.Columns}});
+  ON {{qual_table .SchemaName .TableName}} USING {{.IndexType}} ({{.Columns}}){{if .StorageParameters}} WITH ({{.StorageParameters}}){{end}};

pkg/writers/pgsql/writer.go

@@ -6,8 +6,10 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"regexp"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
@@ -147,8 +149,8 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 		statements = append(statements, fmt.Sprintf("CREATE SCHEMA IF NOT EXISTS %s", schema.SQLName()))
 	}
 
-	if schemaRequiresPGTrgm(schema) {
-		statements = append(statements, `CREATE EXTENSION IF NOT EXISTS pg_trgm`)
+	for _, extension := range requiredExtensions(schema) {
+		statements = append(statements, fmt.Sprintf("CREATE EXTENSION IF NOT EXISTS %s", pgsql.QuoteExtensionName(extension)))
 	}
 
 	// Phase 2: Create sequences
@@ -271,18 +273,12 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				indexType = "btree"
 			}
 
-			// Build column expressions with operator class support for GIN indexes
-			columnExprs := make([]string, 0, len(index.Columns))
-			for _, colName := range index.Columns {
-				colExpr := colName
-				if col, ok := resolveIndexColumn(table, colName); ok {
-					if strings.EqualFold(indexType, "gin") {
-						if opClass := ginOperatorClassForColumn(col, index.Comment); opClass != "" {
-							colExpr = fmt.Sprintf("%s %s", colName, opClass)
-						}
-					}
-				}
-				columnExprs = append(columnExprs, colExpr)
+			// Build column expressions with operator class support (GIN, pgvector, PostGIS)
+			columnExprs := buildIndexColumnExpressions(table, index, indexType)
+
+			withClause := ""
+			if params := indexStorageParameters(index.Comment); params != "" {
+				withClause = fmt.Sprintf(" WITH (%s)", params)
 			}
 
 			whereClause := ""
@@ -290,8 +286,8 @@ func (w *Writer) GenerateSchemaStatements(schema *models.Schema) ([]string, erro
 				whereClause = fmt.Sprintf(" WHERE %s", index.Where)
 			}
 
-			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s",
-				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
+			stmt := fmt.Sprintf("CREATE %sINDEX IF NOT EXISTS %s ON %s USING %s (%s)%s%s",
+				uniqueStr, quoteIdentifier(index.Name), w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, whereClause)
 			statements = append(statements, stmt)
 		}
 	}
@@ -819,11 +815,14 @@ func (w *Writer) writeCreateSchema(schema *models.Schema) error {
 }
 
 func (w *Writer) writeRequiredExtensions(schema *models.Schema) error {
-	if !schemaRequiresPGTrgm(schema) {
+	extensions := requiredExtensions(schema)
+	if len(extensions) == 0 {
 		return nil
 	}
 
-	fmt.Fprintln(w.writer, "CREATE EXTENSION IF NOT EXISTS pg_trgm;")
+	for _, extension := range extensions {
+		fmt.Fprintf(w.writer, "CREATE EXTENSION IF NOT EXISTS %s;\n", pgsql.QuoteExtensionName(extension))
+	}
 	fmt.Fprintln(w.writer)
 	return nil
 }
@@ -1063,21 +1062,13 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 				indexName = fmt.Sprintf("%s_%s_%s", indexType, table.SQLName(), strings.ToLower(columnSuffix))
 			}
 
-			// Build column list with operator class support for GIN indexes
-			columnExprs := make([]string, 0, len(index.Columns))
-			for _, colName := range index.Columns {
-				if col, ok := resolveIndexColumn(table, colName); ok {
-					colExpr := col.SQLName()
-					if strings.EqualFold(index.Type, "gin") {
-						opClass := ginOperatorClassForColumn(col, index.Comment)
-						if opClass != "" {
-							colExpr = fmt.Sprintf("%s %s", col.SQLName(), opClass)
-						}
-					}
-					columnExprs = append(columnExprs, colExpr)
-				}
+			indexType := index.Type
+			if indexType == "" {
+				indexType = "btree"
 			}
 
+			// Build column list with operator class support (GIN, pgvector, PostGIS)
+			columnExprs := buildIndexColumnExpressionsFiltered(table, index, indexType, true)
 			if len(columnExprs) == 0 {
 				continue
 			}
@@ -1087,9 +1078,9 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 				unique = "UNIQUE "
 			}
 
-			indexType := index.Type
-			if indexType == "" {
-				indexType = "btree"
+			withClause := ""
+			if params := indexStorageParameters(index.Comment); params != "" {
+				withClause = fmt.Sprintf(" WITH (%s)", params)
 			}
 
 			whereClause := ""
@@ -1104,8 +1095,8 @@ func (w *Writer) writeIndexes(schema *models.Schema) error {
 
 			fmt.Fprintf(w.writer, "CREATE %sINDEX %sIF NOT EXISTS %s\n",
 				unique, concurrently, indexName)
-			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s;\n\n",
-				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), whereClause)
+			fmt.Fprintf(w.writer, "  ON %s USING %s (%s)%s%s;\n\n",
+				w.qualTable(schema.SQLName(), table.SQLName()), indexType, strings.Join(columnExprs, ", "), withClause, whereClause)
 		}
 	}
 
@@ -1483,7 +1474,69 @@ func isTextTypeWithoutLength(colType string) bool {
 	return strings.EqualFold(colType, "text")
 }
 
-func ginOperatorClassForColumn(col *models.Column, comment string) string {
+// vectorOperatorClasses maps pgvector operator classes to the column base type they
+// apply to. pgvector defines no default operator class, so an hnsw/ivfflat index must
+// always name one explicitly.
+var vectorOperatorClasses = map[string]string{
+	"vector_l2_ops":        "vector",
+	"vector_ip_ops":        "vector",
+	"vector_cosine_ops":    "vector",
+	"vector_l1_ops":        "vector",
+	"halfvec_l2_ops":       "halfvec",
+	"halfvec_ip_ops":       "halfvec",
+	"halfvec_cosine_ops":   "halfvec",
+	"halfvec_l1_ops":       "halfvec",
+	"sparsevec_l2_ops":     "sparsevec",
+	"sparsevec_ip_ops":     "sparsevec",
+	"sparsevec_cosine_ops": "sparsevec",
+	"sparsevec_l1_ops":     "sparsevec",
+	"bit_hamming_ops":      "bit",
+	"bit_jaccard_ops":      "bit",
+}
+
+// defaultVectorOperatorClasses is the operator class used for an hnsw/ivfflat index when
+// the index comment does not request one. Cosine distance is the common default for
+// embedding columns; override it with an "opclass" hint in the index comment.
+var defaultVectorOperatorClasses = map[string]string{
+	"vector":    "vector_cosine_ops",
+	"halfvec":   "halfvec_cosine_ops",
+	"sparsevec": "sparsevec_cosine_ops",
+	"bit":       "bit_hamming_ops",
+}
+
+// spatialOperatorClasses are the PostGIS operator classes recognized in index comments.
+// PostGIS installs default operator classes for gist/spgist/brin, so these are only
+// emitted when explicitly requested (e.g. the 3D/nD variants).
+var spatialOperatorClasses = map[string]bool{
+	"gist_geometry_ops_2d":            true,
+	"gist_geometry_ops_nd":            true,
+	"gist_geography_ops":              true,
+	"spgist_geometry_ops_2d":          true,
+	"spgist_geometry_ops_3d":          true,
+	"spgist_geometry_ops_nd":          true,
+	"brin_geometry_inclusion_ops_2d":  true,
+	"brin_geometry_inclusion_ops_3d":  true,
+	"brin_geometry_inclusion_ops_4d":  true,
+	"brin_geography_inclusion_ops_2d": true,
+	"btree_geometry_ops":              true,
+	"btree_geography_ops":             true,
+}
+
+// isVectorIndexMethod reports whether the access method indexes pgvector types, which
+// covers both pgvector itself (hnsw, ivfflat) and VectorChord (vchordrq, vchordg).
+func isVectorIndexMethod(method string) bool {
+	switch strings.ToLower(strings.TrimSpace(method)) {
+	case "hnsw", "ivfflat", "vchordrq", "vchordg":
+		return true
+	default:
+		return false
+	}
+}
+
+// indexOperatorClassForColumn returns the operator class to emit for a column in an index
+// of the given access method, honouring an explicit request from the index comment when it
+// is compatible with the column type.
+func indexOperatorClassForColumn(col *models.Column, indexType, comment string) string {
 	if col == nil {
 		return ""
 	}
@@ -1492,26 +1545,53 @@ func ginOperatorClassForColumn(col *models.Column, comment string) string {
 	baseType := pgsql.CanonicalizeBaseType(pgsql.ExtractBaseTypeLower(sqlType))
 	isArray := pgsql.IsArrayType(sqlType)
 	requested := extractOperatorClass(comment)
-
-	if requested != "" && ginOperatorClassCompatible(baseType, isArray, requested) {
-		return requested
+	method := strings.ToLower(strings.TrimSpace(indexType))
+	if method == "" {
+		method = "btree"
 	}
 
-	if isArray {
-		return "array_ops"
+	if requested != "" && operatorClassCompatible(method, baseType, isArray, requested) {
+		return requested
 	}
 
 	switch {
-	case isTextGinBaseType(baseType):
-		return "gin_trgm_ops"
-	case baseType == "jsonb":
-		return "jsonb_ops"
+	case method == "gin":
+		if isArray {
+			return "array_ops"
+		}
+		switch {
+		case isTextGinBaseType(baseType):
+			return "gin_trgm_ops"
+		case baseType == "jsonb":
+			return "jsonb_ops"
+		default:
+			return requested
+		}
+	case isVectorIndexMethod(method):
+		if isArray {
+			return ""
+		}
+		return defaultVectorOperatorClasses[baseType]
 	default:
-		return requested
+		// gist/spgist/brin/btree have default operator classes (PostGIS included),
+		// so nothing is emitted unless the comment requested a compatible class.
+		return ""
 	}
 }
 
-func ginOperatorClassCompatible(baseType string, isArray bool, opClass string) bool {
+// ginOperatorClassForColumn is the GIN-specific form of indexOperatorClassForColumn.
+func ginOperatorClassForColumn(col *models.Column, comment string) string {
+	return indexOperatorClassForColumn(col, "gin", comment)
+}
+
+func operatorClassCompatible(method, baseType string, isArray bool, opClass string) bool {
+	if vectorType, ok := vectorOperatorClasses[opClass]; ok {
+		return !isArray && baseType == vectorType && isVectorIndexMethod(method)
+	}
+	if spatialOperatorClasses[opClass] {
+		return !isArray && pgsql.IsSpatialType(baseType)
+	}
+
 	switch opClass {
 	case "gin_trgm_ops", "gin_bigm_ops":
 		return !isArray && isTextGinBaseType(baseType)
@@ -1524,6 +1604,10 @@ func ginOperatorClassCompatible(baseType string, isArray bool, opClass string) b
 	}
 }
 
+func ginOperatorClassCompatible(baseType string, isArray bool, opClass string) bool {
+	return operatorClassCompatible("gin", baseType, isArray, opClass)
+}
+
 func isTextGinBaseType(baseType string) bool {
 	switch baseType {
 	case "text", "varchar", "character varying", "char", "character", "string", "citext", "bpchar":
@@ -1533,29 +1617,188 @@ func isTextGinBaseType(baseType string) bool {
 	}
 }
 
-func schemaRequiresPGTrgm(schema *models.Schema) bool {
+// requiredExtensions returns the PostgreSQL extensions a schema depends on, ordered so
+// that dependencies are created first (postgis before postgis_topology, vector before
+// vchord). Extensions are detected from column types, index access methods, resolved
+// operator classes, and function calls in defaults, check constraints, partial index
+// predicates and view definitions. Extensions that leave no trace in the model (pg_cron,
+// timescaledb, postgres_fdw, …) can be declared in schema.Metadata["extensions"].
+func requiredExtensions(schema *models.Schema) []string {
 	if schema == nil {
-		return false
+		return nil
 	}
+
+	required := make(map[string]bool)
+	add := func(names ...string) {
+		for _, name := range names {
+			if name != "" {
+				required[name] = true
+			}
+		}
+	}
+
+	add(declaredExtensions(schema)...)
+
+	for _, view := range schema.Views {
+		if view == nil {
+			continue
+		}
+		add(pgsql.ExtensionsForExpression(view.Definition)...)
+	}
+
 	for _, table := range schema.Tables {
 		if table == nil {
 			continue
 		}
-		for _, index := range table.Indexes {
-			if index == nil || !strings.EqualFold(index.Type, "gin") {
+
+		for _, col := range table.Columns {
+			if col == nil {
 				continue
 			}
+			add(pgsql.TypeExtension(effectiveColumnSQLType(col)))
+			if def, ok := col.Default.(string); ok {
+				add(pgsql.ExtensionsForExpression(def)...)
+			}
+		}
+
+		for _, constraint := range table.Constraints {
+			if constraint == nil {
+				continue
+			}
+			add(pgsql.ExtensionsForExpression(constraint.Expression)...)
+		}
+
+		for _, index := range table.Indexes {
+			if index == nil {
+				continue
+			}
+			add(pgsql.IndexMethodExtension(index.Type))
+			add(pgsql.ExtensionsForExpression(index.Where)...)
+
 			for _, colName := range index.Columns {
 				col, ok := resolveIndexColumn(table, colName)
 				if !ok || col == nil {
 					continue
 				}
-				if ginOperatorClassForColumn(col, index.Comment) == "gin_trgm_ops" {
-					return true
-				}
+				opClass := indexOperatorClassForColumn(col, index.Type, index.Comment)
+				add(pgsql.OperatorClassExtension(opClass))
+				add(btreeCompanionExtension(index.Type, col, opClass))
 			}
 		}
 	}
+
+	extensions := make([]string, 0, len(required))
+	for ext := range required {
+		extensions = append(extensions, ext)
+	}
+
+	// Pull in dependencies, so a declared postgis_topology also creates postgis.
+	for i := 0; i < len(extensions); i++ {
+		for _, dependency := range pgsql.ExtensionDependencies(extensions[i]) {
+			if !required[dependency] {
+				required[dependency] = true
+				extensions = append(extensions, dependency)
+			}
+		}
+	}
+
+	return pgsql.SortExtensions(extensions)
+}
+
+// declaredExtensions reads schema.Metadata["extensions"], which accepts either a list or a
+// comma-separated string. Unknown names are kept: the metadata is an explicit instruction.
+func declaredExtensions(schema *models.Schema) []string {
+	value, ok := schema.Metadata["extensions"]
+	if !ok {
+		return nil
+	}
+
+	var names []string
+	switch declared := value.(type) {
+	case string:
+		names = strings.Split(declared, ",")
+	case []string:
+		names = declared
+	case []any:
+		for _, item := range declared {
+			if name, ok := item.(string); ok {
+				names = append(names, name)
+			}
+		}
+	default:
+		return nil
+	}
+
+	cleaned := make([]string, 0, len(names))
+	for _, name := range names {
+		if name = strings.TrimSpace(name); name != "" {
+			cleaned = append(cleaned, name)
+		}
+	}
+	return cleaned
+}
+
+// btreeCompanionExtension returns btree_gin or btree_gist when a GIN/GiST index covers a
+// scalar type that neither access method has a built-in operator class for. Without the
+// companion extension PostgreSQL rejects the CREATE INDEX outright.
+func btreeCompanionExtension(indexType string, col *models.Column, opClass string) string {
+	if opClass != "" {
+		return ""
+	}
+
+	method := strings.ToLower(strings.TrimSpace(indexType))
+	if method != "gin" && method != "gist" {
+		return ""
+	}
+
+	sqlType := effectiveColumnSQLType(col)
+	if pgsql.IsArrayType(sqlType) {
+		return ""
+	}
+
+	baseType := pgsql.CanonicalizeBaseType(pgsql.ExtractBaseTypeLower(sqlType))
+	if pgsql.TypeExtension(baseType) != "" {
+		// Extension types (geometry, vector, citext, …) ship their own operator classes.
+		return ""
+	}
+
+	if method == "gin" {
+		if nativeGinBaseType(baseType) {
+			return ""
+		}
+		return "btree_gin"
+	}
+	if nativeGistBaseType(baseType) {
+		return ""
+	}
+	return "btree_gist"
+}
+
+// nativeGinBaseType reports whether core PostgreSQL provides a GIN operator class.
+func nativeGinBaseType(baseType string) bool {
+	switch baseType {
+	case "jsonb", "json", "tsvector", "tsquery":
+		return true
+	default:
+		return false
+	}
+}
+
+// nativeGistBaseType reports whether core PostgreSQL provides a GiST operator class.
+func nativeGistBaseType(baseType string) bool {
+	switch baseType {
+	case "tsvector", "tsquery", "point", "box", "circle", "polygon", "line", "lseg", "path", "inet", "cidr":
+		return true
+	}
+	return strings.HasSuffix(baseType, "range") || strings.HasSuffix(baseType, "multirange")
+}
+
+func schemaRequiresPGTrgm(schema *models.Schema) bool {
+	for _, ext := range requiredExtensions(schema) {
+		if ext == "pg_trgm" {
+			return true
+		}
+	}
 	return false
 }
 
@@ -1642,14 +1885,21 @@ func formatStringList(items []string) string {
 
 // extractOperatorClass extracts operator class from index comment/note
 // Looks for common operator classes like gin_trgm_ops, gist_trgm_ops, etc.
+// explicitOperatorClassPattern matches an "opclass=<name>" hint, the form the PostgreSQL
+// reader uses to carry an index's operator class through the model.
+var explicitOperatorClassPattern = regexp.MustCompile(`(?i)\bopclass\s*=\s*([a-z_][a-z0-9_]*)\b`)
+
 func extractOperatorClass(comment string) string {
 	if comment == "" {
 		return ""
 	}
+
 	lowerComment := strings.ToLower(comment)
-	// Common GIN/GiST operator classes
-	opClasses := []string{"gin_trgm_ops", "gist_trgm_ops", "gin_bigm_ops", "jsonb_ops", "jsonb_path_ops", "array_ops"}
-	for _, op := range opClasses {
+	if matches := explicitOperatorClassPattern.FindStringSubmatch(lowerComment); len(matches) > 1 {
+		return matches[1]
+	}
+
+	for _, op := range knownOperatorClasses() {
 		if strings.Contains(lowerComment, op) {
 			return op
 		}
@@ -1657,6 +1907,35 @@ func extractOperatorClass(comment string) string {
 	return ""
 }
 
+// knownOperatorClasses lists every operator class recognized in an index comment,
+// longest name first so that e.g. gist_geometry_ops_nd wins over a shorter prefix.
+var knownOperatorClasses = sync.OnceValue(func() []string {
+	names := []string{"gin_trgm_ops", "gist_trgm_ops", "gin_bigm_ops", "jsonb_ops", "jsonb_path_ops", "array_ops"}
+	for name := range vectorOperatorClasses {
+		names = append(names, name)
+	}
+	for name := range spatialOperatorClasses {
+		names = append(names, name)
+	}
+	sort.Slice(names, func(i, j int) bool {
+		if len(names[i]) != len(names[j]) {
+			return len(names[i]) > len(names[j])
+		}
+		return names[i] < names[j]
+	})
+	return names
+})
+
+// indexStorageParameters extracts access-method storage parameters from an index comment.
+// Only well-formed "key = value" pairs are kept, so comment prose cannot leak into DDL.
+// Example: "opclass=vector_cosine_ops with (m=16, ef_construction=64)" -> "m = 16, ef_construction = 64".
+func indexStorageParameters(comment string) string {
+	if comment == "" {
+		return ""
+	}
+	return pgsql.FormatStorageParameters(pgsql.ExtractWithClause(comment))
+}
+
 // escapeQuote escapes single quotes in strings for SQL
 func escapeQuote(s string) string {
 	return strings.ReplaceAll(s, "'", "''")

pkg/writers/pgsql/writer_test.go

@@ -1310,3 +1310,203 @@ func TestWriteSchema_UsesStorageTypeForSerialAlterStatements(t *testing.T) {
 		t.Fatalf("expected serial alter to include USING cast, got:\n%s", output)
 	}
 }
+
+// buildVectorSpatialSchema returns a database with a pgvector column and a PostGIS column.
+func buildVectorSpatialSchema(indexType, indexComment string) *models.Database {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	table := models.InitTable("documents", "public")
+
+	embedding := models.InitColumn("embedding", "documents", "public")
+	embedding.Type = "vector(1536)"
+	table.Columns["embedding"] = embedding
+
+	location := models.InitColumn("location", "documents", "public")
+	location.Type = "geometry(Point,4326)"
+	table.Columns["location"] = location
+
+	if indexType != "" {
+		index := &models.Index{
+			Name:    "idx_documents_embedding",
+			Type:    indexType,
+			Columns: []string{"embedding"},
+			Comment: indexComment,
+		}
+		table.Indexes[index.Name] = index
+	}
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+	return db
+}
+
+func writeDatabaseOutput(t *testing.T, db *models.Database) string {
+	t.Helper()
+
+	var buf bytes.Buffer
+	writer := NewWriter(&writers.WriterOptions{})
+	writer.writer = &buf
+
+	if err := writer.WriteDatabase(db); err != nil {
+		t.Fatalf("WriteDatabase failed: %v", err)
+	}
+	return buf.String()
+}
+
+func TestWriteDatabase_VectorAndPostGISColumnsCreateExtensions(t *testing.T) {
+	output := writeDatabaseOutput(t, buildVectorSpatialSchema("", ""))
+
+	for _, want := range []string{
+		"CREATE EXTENSION IF NOT EXISTS postgis;",
+		"CREATE EXTENSION IF NOT EXISTS vector;",
+		"vector(1536)",
+		"geometry(Point,4326)",
+	} {
+		if !strings.Contains(output, want) {
+			t.Fatalf("expected output to contain %q, got:\n%s", want, output)
+		}
+	}
+
+	// postgis must be created before postgis-dependent extensions and stay deterministic
+	if strings.Index(output, "EXISTS postgis;") > strings.Index(output, "EXISTS vector;") {
+		t.Fatalf("expected extensions to be emitted in sorted order, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_HNSWIndexUsesDefaultVectorOperatorClass(t *testing.T) {
+	output := writeDatabaseOutput(t, buildVectorSpatialSchema("hnsw", ""))
+
+	if !strings.Contains(output, "USING hnsw (embedding vector_cosine_ops)") {
+		t.Fatalf("expected hnsw index with default vector operator class, got:\n%s", output)
+	}
+	if !strings.Contains(output, "CREATE EXTENSION IF NOT EXISTS vector;") {
+		t.Fatalf("expected pgvector extension, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_VectorIndexHonoursRequestedOperatorClassAndStorageParameters(t *testing.T) {
+	output := writeDatabaseOutput(t, buildVectorSpatialSchema("ivfflat", "opclass=vector_l2_ops; with (lists=100)"))
+
+	if !strings.Contains(output, "USING ivfflat (embedding vector_l2_ops) WITH (lists = 100)") {
+		t.Fatalf("expected ivfflat index with requested opclass and storage parameters, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_VectorIndexIgnoresIncompatibleOperatorClass(t *testing.T) {
+	output := writeDatabaseOutput(t, buildVectorSpatialSchema("hnsw", "opclass=halfvec_l2_ops"))
+
+	if !strings.Contains(output, "USING hnsw (embedding vector_cosine_ops)") {
+		t.Fatalf("expected halfvec operator class to be rejected for a vector column, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_VectorIndexIgnoresCommentProseInStorageParameters(t *testing.T) {
+	output := writeDatabaseOutput(t, buildVectorSpatialSchema("hnsw", "tuned with (m=16, ef_construction=64, drop table foo)"))
+
+	if !strings.Contains(output, "WITH (m = 16, ef_construction = 64)") {
+		t.Fatalf("expected only well-formed storage parameters, got:\n%s", output)
+	}
+	if strings.Contains(output, "drop table") {
+		t.Fatalf("expected prose to be dropped from storage parameters, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_GistIndexOnGeometryUsesDefaultOperatorClass(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	table := models.InitTable("places", "public")
+	geom := models.InitColumn("geom", "places", "public")
+	geom.Type = "geometry(Point,4326)"
+	table.Columns["geom"] = geom
+
+	table.Indexes["idx_places_geom"] = &models.Index{
+		Name:    "idx_places_geom",
+		Type:    "gist",
+		Columns: []string{"geom"},
+	}
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	output := writeDatabaseOutput(t, db)
+
+	if !strings.Contains(output, "USING gist (geom)") {
+		t.Fatalf("expected gist index to rely on the PostGIS default operator class, got:\n%s", output)
+	}
+}
+
+func TestWriteDatabase_GistIndexHonoursRequestedSpatialOperatorClass(t *testing.T) {
+	db := models.InitDatabase("testdb")
+	schema := models.InitSchema("public")
+
+	table := models.InitTable("places", "public")
+	geom := models.InitColumn("geom", "places", "public")
+	geom.Type = "geometry(PointZ,4326)"
+	table.Columns["geom"] = geom
+
+	table.Indexes["idx_places_geom_nd"] = &models.Index{
+		Name:    "idx_places_geom_nd",
+		Type:    "gist",
+		Columns: []string{"geom"},
+		Comment: "opclass=gist_geometry_ops_nd",
+	}
+
+	schema.Tables = append(schema.Tables, table)
+	db.Schemas = append(db.Schemas, schema)
+
+	output := writeDatabaseOutput(t, db)
+
+	if !strings.Contains(output, "USING gist (geom gist_geometry_ops_nd)") {
+		t.Fatalf("expected requested spatial operator class, got:\n%s", output)
+	}
+}
+
+func TestGenerateDatabaseStatements_VectorIndexIncludesOperatorClassAndParameters(t *testing.T) {
+	db := buildVectorSpatialSchema("hnsw", "opclass=vector_ip_ops; with (m=16)")
+
+	writer := NewWriter(&writers.WriterOptions{})
+	statements, err := writer.GenerateDatabaseStatements(db)
+	if err != nil {
+		t.Fatalf("GenerateDatabaseStatements failed: %v", err)
+	}
+
+	joined := strings.Join(statements, "\n")
+	for _, want := range []string{
+		"CREATE EXTENSION IF NOT EXISTS vector",
+		"CREATE EXTENSION IF NOT EXISTS postgis",
+		"USING hnsw (embedding vector_ip_ops) WITH (m = 16)",
+	} {
+		if !strings.Contains(joined, want) {
+			t.Fatalf("expected statements to contain %q, got:\n%s", want, joined)
+		}
+	}
+}
+
+func TestIndexStorageParameters(t *testing.T) {
+	tests := []struct {
+		name    string
+		comment string
+		want    string
+	}{
+		{"empty", "", ""},
+		{"no with clause", "opclass=vector_cosine_ops", ""},
+		{"single parameter", "with (lists=100)", "lists = 100"},
+		{"multiple parameters", "WITH (m = 16, ef_construction = 64)", "m = 16, ef_construction = 64"},
+		{"quoted value kept", "with (fillfactor='90')", "fillfactor = '90'"},
+		{"bm25 key field", "with (key_field='id')", "key_field = 'id'"},
+		{"dollar quoted value", "with (options = $$[build.internal]\nlists = [4096]$$)", "options = $$[build.internal]\nlists = [4096]$$"},
+		{"dollar quoted value with parens", "with (options = $$f(x)$$, m = 16)", "options = $$f(x)$$, m = 16"},
+		{"prose dropped", "with (lists=100, please drop everything)", "lists = 100"},
+		{"unterminated quote dropped", "with (key_field='id)", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := indexStorageParameters(tt.comment); got != tt.want {
+				t.Errorf("indexStorageParameters(%q) = %q, want %q", tt.comment, got, tt.want)
+			}
+		})
+	}
+}