diff --git a/lsp/source/batch.go b/lsp/source/batch.go
new file mode 100644
index 0000000..6ca15d6
--- /dev/null
+++ b/lsp/source/batch.go
@@ -0,0 +1,43 @@
+package source
+
+import (
+	"context"
+
+	"go.lsp.dev/uri"
+
+	"github.com/karitham/thrift-ls/lsp/cache"
+)
+
+// Batch is the shared analysis context for one diagnostic run. All checkers
+// see the same view and the same cross-file resolver, so a name resolved by
+// one check is not resolved again by the next.
+type Batch struct {
+	view *cache.View
+	ix   *Index
+}
+
+// NewBatch starts an analysis run over the view.
+func NewBatch(view *cache.View) *Batch {
+	return &Batch{view: view}
+}
+
+// View returns the store view this run reads from.
+func (b *Batch) View() *cache.View {
+	return b.view
+}
+
+// Tree returns the parsed tree of uri, parsed and memoized by the view.
+func (b *Batch) Tree(ctx context.Context, u uri.URI) (*cache.ParsedFile, error) {
+	return b.view.Parse(ctx, u)
+}
+
+// Index returns the run's shared cross-file resolver. Resolutions are
+// memoized per (file, name), so repeated lookups across checkers resolve
+// once.
+func (b *Batch) Index() *Index {
+	if b.ix == nil {
+		b.ix = NewIndex(b.view)
+	}
+
+	return b.ix
+}
diff --git a/lsp/source/cycle_detect.go b/lsp/source/cycle_detect.go
index 24a74c7..4f242e3 100644
--- a/lsp/source/cycle_detect.go
+++ b/lsp/source/cycle_detect.go
@@ -18,7 +18,9 @@ import (
 // length are caught, including self-includes.
 type CycleCheck struct{}
 
-func (c *CycleCheck) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (c *CycleCheck) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+	view := b.View()
+
 	closure := make(map[uri.URI][]Include)
 	for _, file := range changeFiles {
 		_ = getIncludes(ctx, view, file, &closure)
diff --git a/lsp/source/cycle_detect_test.go b/lsp/source/cycle_detect_test.go
index 10a465b..4dd1ea9 100644
--- a/lsp/source/cycle_detect_test.go
+++ b/lsp/source/cycle_detect_test.go
@@ -91,7 +91,7 @@ func runCycleCheck(t *testing.T, files map[string]string, root string) []cyclePa
 
 	view := buildSnapshotForTest(t, changes)
 
-	res, err := (&CycleCheck{}).Diagnostic(t.Context(), view, []uri.URI{uri.URI("file:///tmp/" + root)})
+	res, err := (&CycleCheck{}).Diagnostic(t.Context(), NewBatch(view), []uri.URI{uri.URI("file:///tmp/" + root)})
 	require.NoError(t, err)
 
 	for file, diags := range res {
diff --git a/lsp/source/diagnostic.go b/lsp/source/diagnostic.go
index 0bee6ff..e8f215e 100644
--- a/lsp/source/diagnostic.go
+++ b/lsp/source/diagnostic.go
@@ -28,17 +28,21 @@ func init() {
 }
 
 type Checker interface {
-	Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error)
+	Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error)
 	Name() string
 }
 
 type Diagnostic struct{}
 
-func NewDiagnostic() Checker {
+func NewDiagnostic() *Diagnostic {
 	return &Diagnostic{}
 }
 
+// Diagnostic runs every registered checker over changeFiles with a shared
+// Batch, joining their results and errors.
 func (d *Diagnostic) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+	batch := NewBatch(view)
+
 	res := make(DiagnosticResult)
 
 	var errs []error
@@ -46,7 +50,7 @@ func (d *Diagnostic) Diagnostic(ctx context.Context, view *cache.View, changeFil
 	for _, impl := range registry {
 		slog.Debug("diagnostic called", "impl", impl.Name())
 
-		diagRes, err := impl.Diagnostic(ctx, view, changeFiles)
+		diagRes, err := impl.Diagnostic(ctx, batch, changeFiles)
 		if err != nil {
 			errs = append(errs, err)
 		}
diff --git a/lsp/source/duplicate_check.go b/lsp/source/duplicate_check.go
index fc901ee..0799e8a 100644
--- a/lsp/source/duplicate_check.go
+++ b/lsp/source/duplicate_check.go
@@ -26,7 +26,9 @@ func (c *DuplicateCheck) Name() string {
 	return "DuplicateCheck"
 }
 
-func (c *DuplicateCheck) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (c *DuplicateCheck) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+	view := b.View()
+
 	res := make(DiagnosticResult)
 
 	for _, file := range changeFiles {
diff --git a/lsp/source/duplicate_check_test.go b/lsp/source/duplicate_check_test.go
index 213debc..089c7d2 100644
--- a/lsp/source/duplicate_check_test.go
+++ b/lsp/source/duplicate_check_test.go
@@ -359,7 +359,7 @@ enum User {}
 				},
 			})
 
-			got, err := (&DuplicateCheck{}).Diagnostic(t.Context(), view, []uri.URI{"file:///tmp/user.thrift"})
+			got, err := (&DuplicateCheck{}).Diagnostic(t.Context(), NewBatch(view), []uri.URI{"file:///tmp/user.thrift"})
 			assert.NoError(t, err)
 
 			assert.Equal(t, DiagnosticResult{"file:///tmp/user.thrift": tt.want}, got)
diff --git a/lsp/source/enum_value_check.go b/lsp/source/enum_value_check.go
index 4fc3ec1..4f60cee 100644
--- a/lsp/source/enum_value_check.go
+++ b/lsp/source/enum_value_check.go
@@ -22,7 +22,9 @@ type EnumValueCheck struct{}
 // one greater than the preceding member's value otherwise. Their on-wire
 // value therefore follows their position; inserting, removing, or
 // reordering members silently changes serialized data.
-func (c *EnumValueCheck) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (c *EnumValueCheck) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+	view := b.View()
+
 	res := make(DiagnosticResult)
 
 	for _, file := range changeFiles {
diff --git a/lsp/source/enum_value_check_test.go b/lsp/source/enum_value_check_test.go
index 7024b86..d3407fc 100644
--- a/lsp/source/enum_value_check_test.go
+++ b/lsp/source/enum_value_check_test.go
@@ -101,7 +101,7 @@ func Test_EnumValueCheck_Diagnostic(t *testing.T) {
 				},
 			})
 
-			got, err := (&EnumValueCheck{}).Diagnostic(t.Context(), view, []uri.URI{"file:///tmp/user.thrift"})
+			got, err := (&EnumValueCheck{}).Diagnostic(t.Context(), NewBatch(view), []uri.URI{"file:///tmp/user.thrift"})
 			assert.NoError(t, err)
 
 			assert.Equal(t, DiagnosticResult{"file:///tmp/user.thrift": tt.want}, got)
diff --git a/lsp/source/fieldid_check.go b/lsp/source/fieldid_check.go
index 42a4319..69c4977 100644
--- a/lsp/source/fieldid_check.go
+++ b/lsp/source/fieldid_check.go
@@ -17,7 +17,9 @@ type FieldIDCheck struct{}
 
 // FieldIDCheck checks struct, union, exception, function parameter, and
 // throws field ids: they must be unique positive integers in [1, 32767].
-func (c *FieldIDCheck) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (c *FieldIDCheck) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+	view := b.View()
+
 	res := make(DiagnosticResult)
 
 	for _, file := range changeFiles {
diff --git a/lsp/source/fieldid_check_test.go b/lsp/source/fieldid_check_test.go
index b36222c..c220a99 100644
--- a/lsp/source/fieldid_check_test.go
+++ b/lsp/source/fieldid_check_test.go
@@ -411,7 +411,7 @@ service Demo {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			c := &FieldIDCheck{}
-			got, err := c.Diagnostic(tt.args.ctx, tt.args.view, tt.args.changeFiles)
+			got, err := c.Diagnostic(tt.args.ctx, NewBatch(tt.args.view), tt.args.changeFiles)
 
 			for key := range got {
 				sort.SliceStable(got[key], func(i, j int) bool {
diff --git a/lsp/source/include_action_test.go b/lsp/source/include_action_test.go
index cdacdaa..22dfd2f 100644
--- a/lsp/source/include_action_test.go
+++ b/lsp/source/include_action_test.go
@@ -60,7 +60,7 @@ func Test_MakeRemoveUnusedIncludeAction(t *testing.T) {
 	require.NoError(t, err)
 
 	// The diagnostic the check produces, as the server would pass it.
-	diags, err := (&UnusedIncludeCheck{}).diagnostic(t.Context(), view, uri.File(filePath))
+	diags, err := (&UnusedIncludeCheck{}).diagnostic(t.Context(), NewBatch(view), uri.File(filePath))
 	require.NoError(t, err)
 	require.Len(t, diags, 1)
 
diff --git a/lsp/source/index_memo_test.go b/lsp/source/index_memo_test.go
index 52b697f..be05b9e 100644
--- a/lsp/source/index_memo_test.go
+++ b/lsp/source/index_memo_test.go
@@ -197,7 +197,7 @@ func TestSemanticAnalysisSkipsBrokenFile(t *testing.T) {
 				},
 			})
 
-			got, err := (&SemanticAnalysis{}).Diagnostic(t.Context(), view, []uri.URI{"file:///f.thrift"})
+			got, err := (&SemanticAnalysis{}).Diagnostic(t.Context(), NewBatch(view), []uri.URI{"file:///f.thrift"})
 			require.NoError(t, err, "a broken file must not fail the diagnostics run")
 			assert.NotNil(t, got)
 		})
diff --git a/lsp/source/parse.go b/lsp/source/parse.go
index cec1d99..04e824b 100644
--- a/lsp/source/parse.go
+++ b/lsp/source/parse.go
@@ -14,7 +14,9 @@ import (
 
 type Parse struct{}
 
-func (p *Parse) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (p *Parse) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+	view := b.View()
+
 	var errs []error
 
 	res := make(DiagnosticResult)
diff --git a/lsp/source/semantic_analysis.go b/lsp/source/semantic_analysis.go
index dc84014..22d9071 100644
--- a/lsp/source/semantic_analysis.go
+++ b/lsp/source/semantic_analysis.go
@@ -14,11 +14,12 @@ import (
 
 type SemanticAnalysis struct{}
 
-func (s *SemanticAnalysis) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (s *SemanticAnalysis) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
+
 	res := make(DiagnosticResult)
 
 	for _, file := range changeFiles {
-		items, err := s.diagnostic(ctx, view, file)
+		items, err := s.diagnostic(ctx, b, file)
 		if err != nil {
 			return nil, err
 		}
@@ -33,8 +34,8 @@ func (s *SemanticAnalysis) Name() string {
 	return "SemanticAnalysis"
 }
 
-func (s *SemanticAnalysis) diagnostic(ctx context.Context, view *cache.View, changeFile uri.URI) ([]protocol.Diagnostic, error) {
-	pf, err := view.Parse(ctx, changeFile)
+func (s *SemanticAnalysis) diagnostic(ctx context.Context, b *Batch, changeFile uri.URI) ([]protocol.Diagnostic, error) {
+	pf, err := b.Tree(ctx, changeFile)
 	if err != nil {
 		return nil, err
 	}
@@ -50,9 +51,9 @@ func (s *SemanticAnalysis) diagnostic(ctx context.Context, view *cache.View, cha
 		slog.Debug("parse failed", "err", err)
 	}
 
-	// One index per file: resolutions are memoized per (file, name), so
-	// repeated references resolve once.
-	res := s.checkDefinitionExist(ctx, view, NewIndex(view), pf)
+	// The run's shared index: resolutions are memoized per (file, name),
+	// across every checker in the batch.
+	res := s.checkDefinitionExist(ctx, b.View(), b.Index(), pf)
 
 	return res, nil
 }
diff --git a/lsp/source/semantic_analysis_test.go b/lsp/source/semantic_analysis_test.go
index 23220de..cf94e8a 100644
--- a/lsp/source/semantic_analysis_test.go
+++ b/lsp/source/semantic_analysis_test.go
@@ -255,7 +255,7 @@ struct TestUUID {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			c := &SemanticAnalysis{}
-			got, err := c.Diagnostic(tt.args.ctx, tt.args.view, tt.args.changeFiles)
+			got, err := c.Diagnostic(tt.args.ctx, NewBatch(tt.args.view), tt.args.changeFiles)
 
 			for key := range got {
 				sort.SliceStable(got[key], func(i, j int) bool {
@@ -332,7 +332,7 @@ func Test_SemanticAnalysis_MapKeyScalar(t *testing.T) {
 				},
 			})
 
-			got, err := (&SemanticAnalysis{}).diagnostic(t.Context(), view, "file:///tmp/user.thrift")
+			got, err := (&SemanticAnalysis{}).diagnostic(t.Context(), NewBatch(view), "file:///tmp/user.thrift")
 			require.NoError(t, err)
 
 			var msgs []string
diff --git a/lsp/source/unused_include_check.go b/lsp/source/unused_include_check.go
index 8134dbf..dca22b6 100644
--- a/lsp/source/unused_include_check.go
+++ b/lsp/source/unused_include_check.go
@@ -22,11 +22,11 @@ func (c *UnusedIncludeCheck) Name() string {
 	return "UnusedIncludeCheck"
 }
 
-func (c *UnusedIncludeCheck) Diagnostic(ctx context.Context, view *cache.View, changeFiles []uri.URI) (DiagnosticResult, error) {
+func (c *UnusedIncludeCheck) Diagnostic(ctx context.Context, b *Batch, changeFiles []uri.URI) (DiagnosticResult, error) {
 	res := make(DiagnosticResult)
 
 	for _, file := range changeFiles {
-		items, err := c.diagnostic(ctx, view, file)
+		items, err := c.diagnostic(ctx, b, file)
 		if err != nil {
 			return nil, err
 		}
@@ -37,8 +37,8 @@ func (c *UnusedIncludeCheck) Diagnostic(ctx context.Context, view *cache.View, c
 	return res, nil
 }
 
-func (c *UnusedIncludeCheck) diagnostic(ctx context.Context, view *cache.View, file uri.URI) ([]protocol.Diagnostic, error) {
-	pf, err := view.Parse(ctx, file)
+func (c *UnusedIncludeCheck) diagnostic(ctx context.Context, b *Batch, file uri.URI) ([]protocol.Diagnostic, error) {
+	pf, err := b.Tree(ctx, file)
 	if err != nil {
 		return nil, err
 	}
@@ -51,7 +51,7 @@ func (c *UnusedIncludeCheck) diagnostic(ctx context.Context, view *cache.View, f
 		slog.Debug("parse failed", "err", err)
 	}
 
-	return unusedIncludeDiagnostics(ctx, view, file, pf), nil
+	return unusedIncludeDiagnostics(ctx, b, file, pf), nil
 }
 
 // unusedIncludeDiagnostics warns on every include whose target file never
@@ -59,13 +59,13 @@ func (c *UnusedIncludeCheck) diagnostic(ctx context.Context, view *cache.View, f
 // name, a constant value identifier, or a service extends clause, used
 // qualified ("base.Type") or unqualified (resolving through the include
 // chain).
-func unusedIncludeDiagnostics(ctx context.Context, view *cache.View, file uri.URI, pf *cache.ParsedFile) []protocol.Diagnostic {
+func unusedIncludeDiagnostics(ctx context.Context, b *Batch, file uri.URI, pf *cache.ParsedFile) []protocol.Diagnostic {
 	includes := pf.AST().Includes()
 	if len(includes) == 0 {
 		return nil
 	}
 
-	used := usedIncludes(ctx, view, file, pf)
+	used := usedIncludes(ctx, b, file, pf)
 
 	var ret []protocol.Diagnostic
 
@@ -87,11 +87,11 @@ func unusedIncludeDiagnostics(ctx context.Context, view *cache.View, file uri.UR
 }
 
 // usedIncludes marks every include that at least one reference in the
-// document resolves into. Resolution goes through the per-file reference
-// index, which handles both qualified ("base.Type") and unqualified names
-// that resolve through the include chain.
-func usedIncludes(ctx context.Context, view *cache.View, file uri.URI, pf *cache.ParsedFile) map[*syntax.Include]bool {
-	resolver := view.Resolver()
+// document resolves into. Resolution goes through the run's shared
+// cross-file index, which handles both qualified ("base.Type") and
+// unqualified names that resolve through the include chain.
+func usedIncludes(ctx context.Context, b *Batch, file uri.URI, pf *cache.ParsedFile) map[*syntax.Include]bool {
+	resolver := b.View().Resolver()
 	includeByFile := make(map[uri.URI]*syntax.Include)
 
 	for _, inc := range pf.AST().Includes() {
@@ -102,7 +102,7 @@ func usedIncludes(ctx context.Context, view *cache.View, file uri.URI, pf *cache
 
 	used := make(map[*syntax.Include]bool)
 	seen := make(map[string]bool)
-	ix := NewIndex(view)
+	ix := b.Index()
 
 	for _, ref := range pf.Index().References() {
 		if seen[ref.Name] {
diff --git a/lsp/source/unused_include_check_test.go b/lsp/source/unused_include_check_test.go
index f29d283..b4a002c 100644
--- a/lsp/source/unused_include_check_test.go
+++ b/lsp/source/unused_include_check_test.go
@@ -82,7 +82,7 @@ func Test_UnusedIncludeCheck(t *testing.T) {
 				},
 			})
 
-			got, err := (&UnusedIncludeCheck{}).diagnostic(t.Context(), view, uri.File(filePath))
+			got, err := (&UnusedIncludeCheck{}).diagnostic(t.Context(), NewBatch(view), uri.File(filePath))
 			require.NoError(t, err)
 
 			var msgs []string
diff --git a/lsp/source/utf16_test.go b/lsp/source/utf16_test.go
index d12e03a..5d0cb7f 100644
--- a/lsp/source/utf16_test.go
+++ b/lsp/source/utf16_test.go
@@ -87,7 +87,7 @@ func TestParseErrorDiagnosticUTF16(t *testing.T) {
 
 	view := utf16Snapshot(t, src)
 
-	res, err := (&Parse{}).Diagnostic(t.Context(), view, []uri.URI{"file:///tmp/htt.thrift"})
+	res, err := (&Parse{}).Diagnostic(t.Context(), NewBatch(view), []uri.URI{"file:///tmp/htt.thrift"})
 	require.NoError(t, err)
 
 	diags := res["file:///tmp/htt.thrift"]