fix: remove changes from waterfall

.github/workflows/integrationci.yaml

@@ -68,6 +68,7 @@ jobs:
           - semconvfamilies
           - serviceaccount
           - spanmapper
+          - tracedetail
           - querier_json_body
           - querier_skip_resource_fingerprint
           - ttl

docs/api/openapi.yml

@@ -9647,6 +9647,17 @@ components:
       required:
       - aggregations
       type: object
+    SpantypesGettableTraceThread:
+      properties:
+        nextCursor:
+          type: string
+        spans:
+          items:
+            $ref: '#/components/schemas/SpantypesThreadSpan'
+          type: array
+      required:
+      - spans
+      type: object
     SpantypesGettableWaterfallTrace:
       properties:
         endTimestampMillis:
@@ -9961,6 +9972,84 @@ components:
           nullable: true
           type: object
       type: object
+    SpantypesThreadSpan:
+      properties:
+        attributes:
+          additionalProperties: {}
+          nullable: true
+          type: object
+        db_name:
+          type: string
+        db_operation:
+          type: string
+        duration_nano:
+          minimum: 0
+          type: integer
+        events:
+          items:
+            $ref: '#/components/schemas/SpantypesEvent'
+          nullable: true
+          type: array
+        external_http_method:
+          type: string
+        external_http_url:
+          type: string
+        flags:
+          minimum: 0
+          type: integer
+        has_children:
+          type: boolean
+        has_error:
+          type: boolean
+        http_host:
+          type: string
+        http_method:
+          type: string
+        http_url:
+          type: string
+        is_remote:
+          type: string
+        kind_string:
+          type: string
+        level:
+          minimum: 0
+          type: integer
+        name:
+          type: string
+        parent_span_id:
+          type: string
+        references:
+          items:
+            $ref: '#/components/schemas/SpantypesOtelSpanRef'
+          type: array
+        resource:
+          additionalProperties:
+            type: string
+          nullable: true
+          type: object
+        response_status_code:
+          type: string
+        span_id:
+          type: string
+        status_code:
+          type: integer
+        status_code_string:
+          type: string
+        status_message:
+          type: string
+        sub_tree_node_count:
+          minimum: 0
+          type: integer
+        time_unix:
+          minimum: 0
+          type: integer
+        trace_id:
+          type: string
+        trace_state:
+          type: string
+      required:
+      - references
+      type: object
     SpantypesUpdatableSpanMapper:
       properties:
         config:
@@ -15685,6 +15774,80 @@ paths:
       tags:
       - tracedetail
       x-signoz-stability: alpha
+  /api/v1/traces/{traceID}/thread:
+    get:
+      deprecated: false
+      description: Returns the spans carrying gen_ai input or output messages in timestamp
+        order. Pages are fetched with the returned nextCursor.
+      operationId: GetTraceThread
+      parameters:
+      - in: query
+        name: limit
+        schema:
+          type: integer
+      - in: query
+        name: cursor
+        schema:
+          type: string
+      - in: path
+        name: traceID
+        required: true
+        schema:
+          type: string
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                properties:
+                  data:
+                    $ref: '#/components/schemas/SpantypesGettableTraceThread'
+                  status:
+                    type: string
+                required:
+                - status
+                - data
+                type: object
+          description: OK
+        "400":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Bad Request
+        "401":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Unauthorized
+        "403":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Forbidden
+        "404":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Not Found
+        "500":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RenderErrorResponse'
+          description: Internal Server Error
+      security:
+      - api_key:
+        - VIEWER
+      - tokenizer:
+        - VIEWER
+      summary: Get thread view for a trace
+      tags:
+      - tracedetail
+      x-signoz-stability: alpha
   /api/v1/user/me:
     get:
       deprecated: true

frontend/src/api/generated/services/sigNoz.schemas.ts

@@ -11142,6 +11142,157 @@ export interface SpantypesOtelSpanRefDTO {
 	traceId?: string;
 }
 
+export type SpantypesThreadSpanDTOAttributesAnyOf = { [key: string]: unknown };
+
+/**
+ * @nullable
+ */
+export type SpantypesThreadSpanDTOAttributes =
+	SpantypesThreadSpanDTOAttributesAnyOf | null;
+
+export type SpantypesThreadSpanDTOResourceAnyOf = { [key: string]: string };
+
+/**
+ * @nullable
+ */
+export type SpantypesThreadSpanDTOResource =
+	SpantypesThreadSpanDTOResourceAnyOf | null;
+
+export interface SpantypesThreadSpanDTO {
+	/**
+	 * @type object,null
+	 */
+	attributes?: SpantypesThreadSpanDTOAttributes;
+	/**
+	 * @type string
+	 */
+	db_name?: string;
+	/**
+	 * @type string
+	 */
+	db_operation?: string;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	duration_nano?: number;
+	/**
+	 * @type array,null
+	 */
+	events?: SpantypesEventDTO[] | null;
+	/**
+	 * @type string
+	 */
+	external_http_method?: string;
+	/**
+	 * @type string
+	 */
+	external_http_url?: string;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	flags?: number;
+	/**
+	 * @type boolean
+	 */
+	has_children?: boolean;
+	/**
+	 * @type boolean
+	 */
+	has_error?: boolean;
+	/**
+	 * @type string
+	 */
+	http_host?: string;
+	/**
+	 * @type string
+	 */
+	http_method?: string;
+	/**
+	 * @type string
+	 */
+	http_url?: string;
+	/**
+	 * @type string
+	 */
+	is_remote?: string;
+	/**
+	 * @type string
+	 */
+	kind_string?: string;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	level?: number;
+	/**
+	 * @type string
+	 */
+	name?: string;
+	/**
+	 * @type string
+	 */
+	parent_span_id?: string;
+	/**
+	 * @type array
+	 */
+	references: SpantypesOtelSpanRefDTO[];
+	/**
+	 * @type object,null
+	 */
+	resource?: SpantypesThreadSpanDTOResource;
+	/**
+	 * @type string
+	 */
+	response_status_code?: string;
+	/**
+	 * @type string
+	 */
+	span_id?: string;
+	/**
+	 * @type integer
+	 */
+	status_code?: number;
+	/**
+	 * @type string
+	 */
+	status_code_string?: string;
+	/**
+	 * @type string
+	 */
+	status_message?: string;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	sub_tree_node_count?: number;
+	/**
+	 * @type integer
+	 * @minimum 0
+	 */
+	time_unix?: number;
+	/**
+	 * @type string
+	 */
+	trace_id?: string;
+	/**
+	 * @type string
+	 */
+	trace_state?: string;
+}
+
+export interface SpantypesGettableTraceThreadDTO {
+	/**
+	 * @type string
+	 */
+	nextCursor?: string;
+	/**
+	 * @type array
+	 */
+	spans: SpantypesThreadSpanDTO[];
+}
+
 export type SpantypesWaterfallSpanDTOAttributesAnyOf = {
 	[key: string]: unknown;
 };
@@ -12815,6 +12966,30 @@ export type GetTraceAggregations200 = {
 	status: string;
 };
 
+export type GetTraceThreadPathParameters = {
+	traceID: string;
+};
+export type GetTraceThreadParams = {
+	/**
+	 * @type integer
+	 * @description undefined
+	 */
+	limit?: number;
+	/**
+	 * @type string
+	 * @description undefined
+	 */
+	cursor?: string;
+};
+
+export type GetTraceThread200 = {
+	data: SpantypesGettableTraceThreadDTO;
+	/**
+	 * @type string
+	 */
+	status: string;
+};
+
 export type ListUserPreferences200 = {
 	/**
 	 * @type array

frontend/src/api/generated/services/tracedetail/index.ts

@@ -4,11 +4,17 @@
  * * regenerate with 'pnpm generate:api'
  * SigNoz
  */
-import { useMutation } from 'react-query';
+import { useMutation, useQuery } from 'react-query';
 import type {
+	InvalidateOptions,
 	MutationFunction,
+	QueryClient,
+	QueryFunction,
+	QueryKey,
 	UseMutationOptions,
 	UseMutationResult,
+	UseQueryOptions,
+	UseQueryResult,
 } from 'react-query';
 
 import type {
@@ -16,6 +22,9 @@ import type {
 	GetFlamegraphPathParameters,
 	GetTraceAggregations200,
 	GetTraceAggregationsPathParameters,
+	GetTraceThread200,
+	GetTraceThreadParams,
+	GetTraceThreadPathParameters,
 	GetWaterfallV4200,
 	GetWaterfallV4PathParameters,
 	RenderErrorResponseDTO,
@@ -27,6 +36,26 @@ import type {
 import { GeneratedAPIInstance } from '../../../generatedAPIInstance';
 import type { ErrorType, BodyType } from '../../../generatedAPIInstance';
 
+const withQueryKey = <T extends object, K>(
+	query: T,
+	queryKey: K,
+): T & { queryKey: K } => {
+	const result = { queryKey } as T & { queryKey: K };
+	for (const key of Object.keys(query)) {
+		// The explicit queryKey always wins, matching the previous
+		// `{ ...query, queryKey }` spread where it was set last.
+		if (key === 'queryKey') {
+			continue;
+		}
+		Object.defineProperty(result, key, {
+			enumerable: true,
+			configurable: true,
+			get: () => (query as Record<string, unknown>)[key],
+		});
+	}
+	return result;
+};
+
 /**
  * Computes span aggregations grouped by requested field.
  * @summary Get aggregations for a trace
@@ -127,6 +156,121 @@ export const useGetTraceAggregations = <
 > => {
 	return useMutation(getGetTraceAggregationsMutationOptions(options));
 };
+/**
+ * Returns the spans carrying gen_ai input or output messages in timestamp order. Pages are fetched with the returned nextCursor.
+ * @summary Get thread view for a trace
+ */
+export const getTraceThread = (
+	{ traceID }: GetTraceThreadPathParameters,
+	params?: GetTraceThreadParams,
+	signal?: AbortSignal,
+) => {
+	return GeneratedAPIInstance<GetTraceThread200>({
+		url: `/api/v1/traces/${traceID}/thread`,
+		method: 'GET',
+		params,
+		signal,
+	});
+};
+
+export const getGetTraceThreadQueryKey = (
+	{ traceID }: GetTraceThreadPathParameters,
+	params?: GetTraceThreadParams,
+) => {
+	return [
+		`/api/v1/traces/${traceID}/thread`,
+		...(params ? [params] : []),
+	] as const;
+};
+
+export const getGetTraceThreadQueryOptions = <
+	TData = Awaited<ReturnType<typeof getTraceThread>>,
+	TError = ErrorType<RenderErrorResponseDTO>,
+>(
+	{ traceID }: GetTraceThreadPathParameters,
+	params?: GetTraceThreadParams,
+	options?: {
+		query?: UseQueryOptions<
+			Awaited<ReturnType<typeof getTraceThread>>,
+			TError,
+			TData
+		>;
+	},
+) => {
+	const { query: queryOptions } = options ?? {};
+
+	const queryKey =
+		queryOptions?.queryKey ?? getGetTraceThreadQueryKey({ traceID }, params);
+
+	const queryFn: QueryFunction<Awaited<ReturnType<typeof getTraceThread>>> = ({
+		signal,
+	}) => getTraceThread({ traceID }, params, signal);
+
+	return {
+		queryKey,
+		queryFn,
+		enabled: traceID !== null && traceID !== undefined,
+		...queryOptions,
+	} as UseQueryOptions<
+		Awaited<ReturnType<typeof getTraceThread>>,
+		TError,
+		TData
+	> & { queryKey: QueryKey };
+};
+
+export type GetTraceThreadQueryResult = NonNullable<
+	Awaited<ReturnType<typeof getTraceThread>>
+>;
+export type GetTraceThreadQueryError = ErrorType<RenderErrorResponseDTO>;
+
+/**
+ * @summary Get thread view for a trace
+ */
+
+export function useGetTraceThread<
+	TData = Awaited<ReturnType<typeof getTraceThread>>,
+	TError = ErrorType<RenderErrorResponseDTO>,
+>(
+	{ traceID }: GetTraceThreadPathParameters,
+	params?: GetTraceThreadParams,
+	options?: {
+		query?: UseQueryOptions<
+			Awaited<ReturnType<typeof getTraceThread>>,
+			TError,
+			TData
+		>;
+	},
+): UseQueryResult<TData, TError> & { queryKey: QueryKey } {
+	const queryOptions = getGetTraceThreadQueryOptions(
+		{ traceID },
+		params,
+		options,
+	);
+
+	const query = useQuery(queryOptions) as UseQueryResult<TData, TError> & {
+		queryKey: QueryKey;
+	};
+
+	return withQueryKey(query, queryOptions.queryKey);
+}
+
+/**
+ * @summary Get thread view for a trace
+ */
+export const invalidateGetTraceThread = async (
+	queryClient: QueryClient,
+	{ traceID }: GetTraceThreadPathParameters,
+	params?: GetTraceThreadParams,
+	options?: InvalidateOptions,
+): Promise<QueryClient> => {
+	await queryClient.invalidateQueries(
+		{ queryKey: getGetTraceThreadQueryKey({ traceID }, params) },
+		options,
+	);
+
+	return queryClient;
+};
+
 /**
  * Returns the flamegraph view of spans for a given trace ID.
  * @summary Get flamegraph view for a trace

pkg/apiserver/signozapiserver/tracedetail.go

@@ -67,5 +67,23 @@ func (provider *provider) addTraceDetailRoutes(router *mux.Router) error {
 		return err
 	}
 
+	if err := router.Handle("/api/v1/traces/{traceID}/thread", handler.New(
+		provider.authzMiddleware.ViewAccess(provider.traceDetailHandler.GetThread),
+		handler.OpenAPIDef{
+			ID:                  "GetTraceThread",
+			Tags:                []string{"tracedetail"},
+			Summary:             "Get thread view for a trace",
+			Description:         "Returns the spans carrying gen_ai input or output messages in timestamp order. Pages are fetched with the returned nextCursor.",
+			RequestQuery:        new(spantypes.QueryableThread),
+			Response:            new(spantypes.GettableTraceThread),
+			ResponseContentType: "application/json",
+			SuccessStatusCode:   http.StatusOK,
+			ErrorStatusCodes:    []int{http.StatusBadRequest, http.StatusNotFound},
+			SecuritySchemes:     newSecuritySchemes(types.RoleViewer),
+		},
+	)).Methods(http.MethodGet).GetError(); err != nil {
+		return err
+	}
+
 	return nil
 }

pkg/modules/tracedetail/impltracedetail/handler.go

@@ -75,3 +75,25 @@ func (h *handler) GetFlamegraph(rw http.ResponseWriter, r *http.Request) {
 
 	render.Success(rw, http.StatusOK, result)
 }
+
+func (h *handler) GetThread(rw http.ResponseWriter, r *http.Request) {
+	req := new(spantypes.QueryableThread)
+	if err := binding.Query.BindQuery(r.URL.Query(), req); err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	query, err := spantypes.NewThreadQuery(req)
+	if err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	result, err := h.module.GetThread(r.Context(), mux.Vars(r)["traceID"], query)
+	if err != nil {
+		render.Error(rw, err)
+		return
+	}
+
+	render.Success(rw, http.StatusOK, result)
+}

pkg/modules/tracedetail/impltracedetail/module.go

@@ -173,6 +173,19 @@ func (m *module) getWindowedWaterfall(ctx context.Context, traceID, selectedSpan
 	), nil
 }
 
+func (m *module) GetThread(ctx context.Context, traceID string, query *spantypes.ThreadQuery) (*spantypes.GettableTraceThread, error) {
+	summary, err := m.store.GetTraceSummary(ctx, traceID)
+	if err != nil {
+		return nil, err
+	}
+
+	spans, err := m.store.GetThreadSpans(ctx, traceID, summary, query.Cursor, query.Limit+1)
+	if err != nil {
+		return nil, err
+	}
+	return spantypes.NewGettableTraceThread(traceID, spans, query.Limit), nil
+}
+
 func (m *module) getFullFlamegraph(ctx context.Context, traceID string, summary *spantypes.TraceSummary, selectFields []telemetrytypes.TelemetryFieldKey) (*spantypes.GettableFlamegraphTrace, error) {
 	fullSpans, err := m.store.GetFlamegraphSpans(ctx, traceID, summary.Start, summary.End, nil)
 	if err != nil {

pkg/modules/tracedetail/impltracedetail/store.go

@@ -11,12 +11,23 @@ import (
 	"github.com/SigNoz/signoz/pkg/clickhousesql"
 	"github.com/SigNoz/signoz/pkg/errors"
 	"github.com/SigNoz/signoz/pkg/telemetrystore"
+	"github.com/SigNoz/signoz/pkg/types/aiobservabilitytypes"
 	"github.com/SigNoz/signoz/pkg/types/spantypes"
 	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
 )
 
 const colServiceName = `resource_string_service$$$$name` // $ gets escaped so $$$$ converts to $$.
 
+var fullSpanColumns = []string{
+	"duration_nano", "span_id", "has_error", "kind",
+	colServiceName, "name",
+	"attributes_string", "attributes_number", "attributes_bool", "resources_string",
+	"events", "status_message", "status_code_string", "kind_string", "parent_span_id",
+	"flags", "is_remote", "trace_state", "status_code",
+	"db_name", "db_operation", "http_method", "http_url", "http_host",
+	"external_http_method", "external_http_url", "response_status_code", "links as references",
+}
+
 func buildFieldExpr(fieldKey telemetrytypes.TelemetryFieldKey) (string, error) {
 	switch fieldKey.FieldContext {
 	case telemetrytypes.FieldContextResource:
@@ -123,16 +134,8 @@ func (s *traceStore) GetTraceSpansByIDs(ctx context.Context, traceID string, sta
 		return []spantypes.StorableSpan{}, nil
 	}
 	sb := sqlbuilder.NewSelectBuilder()
-	sb.Select(
-		"DISTINCT ON (span_id) timestamp",
-		"duration_nano", "span_id", "has_error", "kind",
-		colServiceName, "name",
-		"attributes_string", "attributes_number", "attributes_bool", "resources_string",
-		"events", "status_message", "status_code_string", "kind_string", "parent_span_id",
-		"flags", "is_remote", "trace_state", "status_code",
-		"db_name", "db_operation", "http_method", "http_url", "http_host",
-		"external_http_method", "external_http_url", "response_status_code", "links as references",
-	)
+	sb.Select("DISTINCT ON (span_id) timestamp")
+	sb.SelectMore(fullSpanColumns...)
 	sb.From(fmt.Sprintf("%s.%s", spantypes.TraceDB, spantypes.TraceTable))
 	ids := make([]any, len(spanIDs))
 	for i, id := range spanIDs {
@@ -155,6 +158,44 @@ func (s *traceStore) GetTraceSpansByIDs(ctx context.Context, traceID string, sta
 	return spans, nil
 }
 
+func (s *traceStore) GetThreadSpans(ctx context.Context, traceID string, summary *spantypes.TraceSummary, cursor *spantypes.ThreadCursor, limit int) ([]spantypes.StorableSpan, error) {
+	sb := sqlbuilder.NewSelectBuilder()
+	sb.Select("DISTINCT ON (span_id) timestamp")
+	sb.SelectMore(fullSpanColumns...)
+	sb.SelectMore("attributes")
+	sb.From(fmt.Sprintf("%s.%s", spantypes.TraceDB, spantypes.TraceTable))
+	sb.Where(
+		sb.E("trace_id", traceID),
+		sb.GE("ts_bucket_start", summary.Start.Unix()-1800),
+		sb.LE("ts_bucket_start", summary.End.Unix()),
+		// Reads only the JSON column; spans with messages only in the legacy maps are skipped.
+		// todo(nitya): pick the column from the attribute evolution metadata.
+		sb.Or(
+			sqlbuilder.Escape(fmt.Sprintf("attributes.%s IS NOT NULL", clickhousesql.Identifier(aiobservabilitytypes.GenAIInputMessages))),
+			sqlbuilder.Escape(fmt.Sprintf("attributes.%s IS NOT NULL", clickhousesql.Identifier(aiobservabilitytypes.GenAIOutputMessages))),
+		),
+	)
+	if cursor != nil {
+		// ClickHouse can't use an index for a tuple comparison, so the separate timestamp and
+		// ts_bucket_start bounds are what skip the data before the cursor.
+		sb.Where(
+			sb.GE("ts_bucket_start", int64(cursor.TimeUnixNano/uint64(time.Second))-1800),
+			sb.GE("timestamp", fmt.Sprintf("%d", cursor.TimeUnixNano)),
+			sb.GT("(toUnixTimestamp64Nano(timestamp), span_id)", sqlbuilder.Tuple(cursor.TimeUnixNano, cursor.SpanID)),
+		)
+	}
+	sb.OrderByAsc("timestamp")
+	sb.OrderByAsc("span_id")
+	sb.Limit(limit)
+	query, args := sb.BuildWithFlavor(sqlbuilder.ClickHouse)
+
+	var spans []spantypes.StorableSpan
+	if err := s.telemetryStore.ClickhouseDB().Select(ctx, &spans, query, args...); err != nil {
+		return nil, errors.WrapInternalf(err, errors.CodeInternal, "error querying thread spans")
+	}
+	return spans, nil
+}
+
 func (s *traceStore) GetFlamegraphSpans(ctx context.Context, traceID string, start, end time.Time, spanIDs []string) ([]spantypes.StorableSpan, error) {
 	sb := sqlbuilder.NewSelectBuilder()
 	sb.Select(

pkg/modules/tracedetail/tracedetail.go

@@ -13,6 +13,7 @@ type Handler interface {
 	GetWaterfallV4(http.ResponseWriter, *http.Request)
 	GetTraceAggregations(http.ResponseWriter, *http.Request)
 	GetFlamegraph(http.ResponseWriter, *http.Request)
+	GetThread(http.ResponseWriter, *http.Request)
 }
 
 // Module defines the business logic for trace detail operations.
@@ -20,4 +21,5 @@ type Module interface {
 	GetWaterfallV4(ctx context.Context, traceID string, selectedSpanID string, uncollapsedSpans []string) (*spantypes.GettableWaterfallTrace, error)
 	GetTraceAggregations(ctx context.Context, traceID string, req *spantypes.PostableTraceAggregations) (*spantypes.GettableTraceAggregations, error)
 	GetFlamegraph(ctx context.Context, traceID string, selectedSpanID string, selectFields []telemetrytypes.TelemetryFieldKey) (*spantypes.GettableFlamegraphTrace, error)
+	GetThread(ctx context.Context, traceID string, query *spantypes.ThreadQuery) (*spantypes.GettableTraceThread, error)
 }

pkg/querier/consume.go

@@ -566,24 +566,6 @@ func readAsRaw(rows driver.Rows, queryName string) (*qbtypes.RawData, error) {
 	}, nil
 }
 
-// flattenJSONPaths flattens a decoded JSON document into dotted keys, overwriting existing keys in out.
-func flattenJSONPaths(prefix string, m map[string]any, out map[string]any) {
-	for k, v := range m {
-		key := k
-		if prefix != "" {
-			key = prefix + "." + k
-		}
-		switch child := v.(type) {
-		case map[string]any:
-			flattenJSONPaths(key, child, out)
-		case telemetrystoretypes.JSONValue:
-			flattenJSONPaths(key, child, out)
-		default:
-			out[key] = v
-		}
-	}
-}
-
 // mergeSpanAttributeColumns merges (attributes_string, attributes_number, attributes_bool, resources_string) into
 // unified "attributes" and "resource" keys, and parses the stringified `events`
 // and `links` columns into structured slices. Raw DB columns are removed.
@@ -598,7 +580,7 @@ func mergeSpanAttributeColumns(data map[string]any) {
 	resStr, hasRes := data["resources_string"]
 	if hasStr || hasNum || hasBool || attrJSON != nil || hasRes {
 		attributes := make(map[string]any)
-		flattenJSONPaths("", attrJSON, attributes)
+		attrJSON.FlattenInto("", attributes)
 		if m, ok := attrStr.(map[string]string); ok {
 			for k, v := range m {
 				attributes[k] = v

pkg/types/spantypes/store.go

@@ -36,6 +36,7 @@ type TraceStore interface {
 	GetMinimalSpans(ctx context.Context, traceID string, start, end time.Time) ([]MinimalSpan, error)
 	GetTraceSpansByIDs(ctx context.Context, traceID string, start, end time.Time, spanIDs []string) ([]StorableSpan, error)
 	GetFlamegraphSpans(ctx context.Context, traceID string, start, end time.Time, spanIDs []string) ([]StorableSpan, error)
+	GetThreadSpans(ctx context.Context, traceID string, summary *TraceSummary, cursor *ThreadCursor, limit int) ([]StorableSpan, error)
 
 	GetSpanCountByField(ctx context.Context, traceID string, summary *TraceSummary, fieldKey telemetrytypes.TelemetryFieldKey) (map[string]uint64, error)
 	GetSpanDurationByField(ctx context.Context, traceID string, summary *TraceSummary, fieldKey telemetrytypes.TelemetryFieldKey) (map[string]uint64, error)

pkg/types/spantypes/thread.go

@@ -0,0 +1,113 @@
+package spantypes
+
+import (
+	"encoding/base64"
+	"encoding/json"
+
+	"github.com/SigNoz/signoz/pkg/errors"
+)
+
+const (
+	threadDefaultLimit = 100
+	threadMaxLimit     = 1000
+)
+
+var (
+	ErrCodeThreadInvalidLimit  = errors.MustNewCode("trace_thread_invalid_limit")
+	ErrCodeThreadInvalidCursor = errors.MustNewCode("trace_thread_invalid_cursor")
+)
+
+type QueryableThread struct {
+	// Limit is the page size; 0 means 100.
+	Limit int `query:"limit"`
+	// Cursor is the nextCursor of the previous page; empty for the first page.
+	Cursor string `query:"cursor"`
+}
+
+type ThreadQuery struct {
+	Limit  int
+	Cursor *ThreadCursor
+}
+
+func NewThreadQuery(queryable *QueryableThread) (*ThreadQuery, error) {
+	query := &ThreadQuery{Limit: queryable.Limit}
+	if query.Limit < 0 {
+		return nil, errors.NewInvalidInputf(ErrCodeThreadInvalidLimit, "limit cannot be negative, got %d", query.Limit)
+	}
+	if query.Limit == 0 {
+		query.Limit = threadDefaultLimit
+	}
+	if query.Limit > threadMaxLimit {
+		return nil, errors.NewInvalidInputf(ErrCodeThreadInvalidLimit, "limit cannot exceed %d, got %d", threadMaxLimit, query.Limit)
+	}
+	if queryable.Cursor != "" {
+		cursor, err := DecodeThreadCursor(queryable.Cursor)
+		if err != nil {
+			return nil, err
+		}
+		query.Cursor = cursor
+	}
+	return query, nil
+}
+
+// ThreadCursor is the (TimeUnixNano, SpanID) of the last span of a page.
+type ThreadCursor struct {
+	TimeUnixNano uint64 `json:"t"`
+	SpanID       string `json:"s"`
+}
+
+func (c ThreadCursor) Encode() string {
+	data, _ := json.Marshal(c)
+	return base64.RawURLEncoding.EncodeToString(data)
+}
+
+func DecodeThreadCursor(cursor string) (*ThreadCursor, error) {
+	data, err := base64.RawURLEncoding.DecodeString(cursor)
+	if err != nil {
+		return nil, errors.WrapInvalidInputf(err, ErrCodeThreadInvalidCursor, "invalid cursor")
+	}
+	c := new(ThreadCursor)
+	if err := json.Unmarshal(data, c); err != nil {
+		return nil, errors.WrapInvalidInputf(err, ErrCodeThreadInvalidCursor, "invalid cursor")
+	}
+	if c.SpanID == "" {
+		return nil, errors.NewInvalidInputf(ErrCodeThreadInvalidCursor, "invalid cursor: missing span id")
+	}
+	return c, nil
+}
+
+type GettableTraceThread struct {
+	Spans      []*ThreadSpan `json:"spans" required:"true" nullable:"false"`
+	NextCursor string        `json:"nextCursor,omitempty"`
+}
+
+type ThreadSpan struct {
+	WaterfallSpan
+}
+
+// NewGettableTraceThread expects limit+1 spans; the extra one only signals a next page.
+func NewGettableTraceThread(traceID string, spans []StorableSpan, limit int) *GettableTraceThread {
+	hasMore := len(spans) > limit
+	if hasMore {
+		spans = spans[:limit]
+	}
+
+	out := make([]*ThreadSpan, len(spans))
+	for i := range spans {
+		out[i] = newThreadSpan(traceID, &spans[i])
+	}
+
+	thread := &GettableTraceThread{Spans: out}
+	if hasMore {
+		last := spans[len(spans)-1]
+		thread.NextCursor = ThreadCursor{TimeUnixNano: uint64(last.StartTime.UnixNano()), SpanID: last.SpanID}.Encode()
+	}
+	return thread
+}
+
+func newThreadSpan(traceID string, storable *StorableSpan) *ThreadSpan {
+	span := &ThreadSpan{WaterfallSpan: *storable.ToWaterfallSpan(traceID)}
+	// client expects millis, as in the waterfall
+	span.TimeUnix = span.TimeUnix / 1_000_000
+	return span
+}

pkg/types/spantypes/thread_test.go

@@ -0,0 +1,102 @@
+package spantypes
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewThreadQuery(t *testing.T) {
+	cursor := ThreadCursor{TimeUnixNano: 1757500000123456789, SpanID: "f1fa1bc863e94dd0"}
+
+	testCases := []struct {
+		name      string
+		queryable QueryableThread
+		want      *ThreadQuery
+		wantErr   bool
+	}{
+		{name: "ZeroLimit_UsesDefault", queryable: QueryableThread{}, want: &ThreadQuery{Limit: threadDefaultLimit}},
+		{name: "PositiveLimit_Kept", queryable: QueryableThread{Limit: 25}, want: &ThreadQuery{Limit: 25}},
+		{name: "MaxLimit_Kept", queryable: QueryableThread{Limit: threadMaxLimit}, want: &ThreadQuery{Limit: threadMaxLimit}},
+		{name: "AboveMaxLimit_Rejected", queryable: QueryableThread{Limit: threadMaxLimit + 1}, wantErr: true},
+		{name: "NegativeLimit_Rejected", queryable: QueryableThread{Limit: -1}, wantErr: true},
+		{name: "Cursor_Decoded", queryable: QueryableThread{Limit: 10, Cursor: cursor.Encode()}, want: &ThreadQuery{Limit: 10, Cursor: &cursor}},
+		{name: "InvalidCursor_Rejected", queryable: QueryableThread{Cursor: "not base64!"}, wantErr: true},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			got, err := NewThreadQuery(&testCase.queryable)
+			if testCase.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, testCase.want, got)
+		})
+	}
+}
+
+func TestDecodeThreadCursor(t *testing.T) {
+	testCases := []struct {
+		name    string
+		cursor  string
+		want    *ThreadCursor
+		wantErr bool
+	}{
+		{name: "EncodedCursor_RoundTrips", cursor: ThreadCursor{TimeUnixNano: 1757500000123456789, SpanID: "f1fa1bc863e94dd0"}.Encode(), want: &ThreadCursor{TimeUnixNano: 1757500000123456789, SpanID: "f1fa1bc863e94dd0"}},
+		{name: "NotBase64_Rejected", cursor: "not base64!", wantErr: true},
+		{name: "NotJSON_Rejected", cursor: "bm90IGpzb24", wantErr: true},
+		{name: "MissingSpanID_Rejected", cursor: "eyJ0IjogMX0", wantErr: true},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			got, err := DecodeThreadCursor(testCase.cursor)
+			if testCase.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, testCase.want, got)
+		})
+	}
+}
+
+func TestNewGettableTraceThread(t *testing.T) {
+	spans := []StorableSpan{
+		{SpanID: "a", StartTime: time.Unix(1, 500_000_000)},
+		{SpanID: "b", StartTime: time.Unix(2, 0)},
+		{SpanID: "c", StartTime: time.Unix(3, 0)},
+	}
+
+	testCases := []struct {
+		name           string
+		spans          []StorableSpan
+		limit          int
+		wantSpanIDs    []string
+		wantTimeUnix   []uint64
+		wantNextCursor string
+	}{
+		{name: "MoreThanLimit_TrimsAndSetsCursor", spans: spans, limit: 2, wantSpanIDs: []string{"a", "b"}, wantTimeUnix: []uint64{1500, 2000}, wantNextCursor: ThreadCursor{TimeUnixNano: 2_000_000_000, SpanID: "b"}.Encode()},
+		{name: "WithinLimit_NoCursor", spans: spans, limit: 3, wantSpanIDs: []string{"a", "b", "c"}, wantTimeUnix: []uint64{1500, 2000, 3000}},
+		{name: "NoSpans_EmptyList", limit: 3, wantSpanIDs: []string{}, wantTimeUnix: []uint64{}},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			thread := NewGettableTraceThread("trace-1", testCase.spans, testCase.limit)
+			require.NotNil(t, thread.Spans)
+			spanIDs := make([]string, len(thread.Spans))
+			timeUnix := make([]uint64, len(thread.Spans))
+			for i, span := range thread.Spans {
+				spanIDs[i] = span.SpanID
+				timeUnix[i] = span.TimeUnix
+				assert.Equal(t, "trace-1", span.TraceID)
+			}
+			assert.Equal(t, testCase.wantSpanIDs, spanIDs)
+			assert.Equal(t, testCase.wantTimeUnix, timeUnix)
+			assert.Equal(t, testCase.wantNextCursor, thread.NextCursor)
+		})
+	}
+
+}

pkg/types/spantypes/waterfall_span.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/SigNoz/signoz/pkg/errors"
+	"github.com/SigNoz/signoz/pkg/types/telemetrystoretypes"
 	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
 )
 
@@ -93,35 +94,36 @@ type WaterfallSpan struct {
 
 // StorableSpan is the ClickHouse scan struct for the v3 waterfall query.
 type StorableSpan struct {
-	StartTime          time.Time          `ch:"timestamp"`
-	DurationNano       uint64             `ch:"duration_nano"`
-	SpanID             string             `ch:"span_id"`
-	HasError           bool               `ch:"has_error"`
-	Kind               int8               `ch:"kind"`
-	ServiceName        string             `ch:"resource_string_service$$name"`
-	Name               string             `ch:"name"`
-	AttributesString   map[string]string  `ch:"attributes_string"`
-	AttributesNumber   map[string]float64 `ch:"attributes_number"`
-	AttributesBool     map[string]bool    `ch:"attributes_bool"`
-	ResourcesString    map[string]string  `ch:"resources_string"`
-	Events             []string           `ch:"events"`
-	StatusMessage      string             `ch:"status_message"`
-	StatusCodeString   string             `ch:"status_code_string"`
-	SpanKind           string             `ch:"kind_string"`
-	ParentSpanID       string             `ch:"parent_span_id"`
-	Flags              uint32             `ch:"flags"`
-	IsRemote           string             `ch:"is_remote"`
-	TraceState         string             `ch:"trace_state"`
-	StatusCode         int16              `ch:"status_code"`
-	DBName             string             `ch:"db_name"`
-	DBOperation        string             `ch:"db_operation"`
-	HTTPMethod         string             `ch:"http_method"`
-	HTTPURL            string             `ch:"http_url"`
-	HTTPHost           string             `ch:"http_host"`
-	ExternalHTTPMethod string             `ch:"external_http_method"`
-	ExternalHTTPURL    string             `ch:"external_http_url"`
-	ResponseStatusCode string             `ch:"response_status_code"`
-	References         string             `ch:"references"`
+	StartTime          time.Time                     `ch:"timestamp"`
+	DurationNano       uint64                        `ch:"duration_nano"`
+	SpanID             string                        `ch:"span_id"`
+	HasError           bool                          `ch:"has_error"`
+	Kind               int8                          `ch:"kind"`
+	ServiceName        string                        `ch:"resource_string_service$$name"`
+	Name               string                        `ch:"name"`
+	AttributesString   map[string]string             `ch:"attributes_string"`
+	AttributesNumber   map[string]float64            `ch:"attributes_number"`
+	AttributesBool     map[string]bool               `ch:"attributes_bool"`
+	AttributesJSON     telemetrystoretypes.JSONValue `ch:"attributes"`
+	ResourcesString    map[string]string             `ch:"resources_string"`
+	Events             []string                      `ch:"events"`
+	StatusMessage      string                        `ch:"status_message"`
+	StatusCodeString   string                        `ch:"status_code_string"`
+	SpanKind           string                        `ch:"kind_string"`
+	ParentSpanID       string                        `ch:"parent_span_id"`
+	Flags              uint32                        `ch:"flags"`
+	IsRemote           string                        `ch:"is_remote"`
+	TraceState         string                        `ch:"trace_state"`
+	StatusCode         int16                         `ch:"status_code"`
+	DBName             string                        `ch:"db_name"`
+	DBOperation        string                        `ch:"db_operation"`
+	HTTPMethod         string                        `ch:"http_method"`
+	HTTPURL            string                        `ch:"http_url"`
+	HTTPHost           string                        `ch:"http_host"`
+	ExternalHTTPMethod string                        `ch:"external_http_method"`
+	ExternalHTTPURL    string                        `ch:"external_http_url"`
+	ResponseStatusCode string                        `ch:"response_status_code"`
+	References         string                        `ch:"references"`
 }
 
 // MinimalSpan with only the fields needed to build the parent-child tree.
@@ -277,8 +279,10 @@ func (item *StorableSpan) AttributeValue(name string) any {
 	return nil
 }
 
+// Attributes flattens the JSON column first, so the legacy maps win on collision.
 func (item *StorableSpan) Attributes() map[string]any {
-	attributes := make(map[string]any, len(item.AttributesString)+len(item.AttributesNumber)+len(item.AttributesBool))
+	attributes := make(map[string]any, len(item.AttributesString)+len(item.AttributesNumber)+len(item.AttributesBool)+len(item.AttributesJSON))
+	item.AttributesJSON.FlattenInto("", attributes)
 	for k, v := range item.AttributesString {
 		attributes[k] = v
 	}

pkg/types/spantypes/waterfall_span_test.go

@@ -0,0 +1,59 @@
+package spantypes
+
+import (
+	"testing"
+
+	"github.com/SigNoz/signoz/pkg/types/telemetrystoretypes"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStorableSpanAttributes(t *testing.T) {
+	testCases := []struct {
+		name      string
+		span      StorableSpan
+		wantAttrs map[string]any
+	}{
+		{
+			name: "LegacyMapOnly_Kept",
+			span: StorableSpan{AttributesString: map[string]string{
+				"gen_ai.input.messages":  `[{"role":"user","parts":[{"type":"text","content":"hi"}]}]`,
+				"gen_ai.output.messages": `[{"role":"assistant","parts":[{"type":"text","content":"hello"}],"finish_reason":"stop"}]`,
+			}},
+			wantAttrs: map[string]any{
+				"gen_ai.input.messages":  `[{"role":"user","parts":[{"type":"text","content":"hi"}]}]`,
+				"gen_ai.output.messages": `[{"role":"assistant","parts":[{"type":"text","content":"hello"}],"finish_reason":"stop"}]`,
+			},
+		},
+		{
+			name: "JSONColumn_FlattenedToDottedKeys",
+			span: StorableSpan{AttributesJSON: telemetrystoretypes.JSONValue{
+				"gen_ai": map[string]any{
+					"input":   map[string]any{"messages": `[{"role":"user","content":"hi"}]`},
+					"request": map[string]any{"model": "gpt-4o"},
+				},
+			}},
+			wantAttrs: map[string]any{
+				"gen_ai.input.messages": `[{"role":"user","content":"hi"}]`,
+				"gen_ai.request.model":  "gpt-4o",
+			},
+		},
+		{
+			name: "LegacyMapWinsOverJSONColumn",
+			span: StorableSpan{
+				AttributesJSON:   telemetrystoretypes.JSONValue{"gen_ai": map[string]any{"request": map[string]any{"model": "json"}}},
+				AttributesString: map[string]string{"gen_ai.request.model": "map"},
+			},
+			wantAttrs: map[string]any{"gen_ai.request.model": "map"},
+		},
+		{
+			name:      "NoMessages_AttributesKept",
+			span:      StorableSpan{AttributesString: map[string]string{"http.method": "GET"}},
+			wantAttrs: map[string]any{"http.method": "GET"},
+		},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			assert.Equal(t, testCase.wantAttrs, testCase.span.Attributes())
+		})
+	}
+}

pkg/types/telemetrystoretypes/json.go

@@ -35,3 +35,21 @@ func (v *JSONValue) Scan(src any) error {
 	*v = decoded
 	return nil
 }
+
+// FlattenInto writes v into out under dotted keys, overwriting existing keys.
+func (v JSONValue) FlattenInto(prefix string, out map[string]any) {
+	for k, value := range v {
+		key := k
+		if prefix != "" {
+			key = prefix + "." + k
+		}
+		switch child := value.(type) {
+		case map[string]any:
+			JSONValue(child).FlattenInto(key, out)
+		case JSONValue:
+			child.FlattenInto(key, out)
+		default:
+			out[key] = value
+		}
+	}
+}

tests/integration/tests/tracedetail/01_thread.py

@@ -0,0 +1,127 @@
+import json
+from collections.abc import Callable
+from datetime import UTC, datetime, timedelta
+from http import HTTPStatus
+
+import requests
+
+from fixtures import types
+from fixtures.auth import USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD
+from fixtures.traces import TraceIdGenerator, Traces, TracesKind
+
+
+def test_thread_returns_message_spans_in_order(
+    signoz: types.SigNoz,
+    create_user_admin: None,  # pylint: disable=unused-argument
+    get_token: Callable[[str, str], str],
+    insert_traces: Callable[[list[Traces]], None],
+) -> None:
+    now = datetime.now(tz=UTC).replace(microsecond=0)
+    trace_id = TraceIdGenerator.trace_id()
+    root_id, first_llm_id, tool_id, second_llm_id, third_llm_id = (TraceIdGenerator.span_id() for _ in range(5))
+    resources = {"service.name": "tracedetail-thread"}
+    first_input = json.dumps([{"role": "user", "parts": [{"type": "text", "content": "weather in Bangalore?"}]}])
+    first_output = json.dumps([{"role": "assistant", "parts": [{"type": "tool_call", "id": "call_1", "name": "get_weather", "arguments": {"city": "Bangalore"}}], "finish_reason": "tool_call"}])
+    second_input = json.dumps([{"role": "tool", "content": "sunny", "tool_call_id": "call_1"}])
+
+    insert_traces(
+        [
+            Traces(timestamp=now - timedelta(seconds=10), duration=timedelta(seconds=9), trace_id=trace_id, span_id=root_id, name="POST /chat", kind=TracesKind.SPAN_KIND_SERVER, resources=resources, attribute_write_mode="json_only"),
+            Traces(
+                timestamp=now - timedelta(seconds=8), trace_id=trace_id, span_id=first_llm_id, parent_span_id=root_id, name="chat gpt-4o", resources=resources, attributes={"gen_ai.request.model": "gpt-4o", "gen_ai.input.messages": first_input, "gen_ai.output.messages": first_output}, attribute_write_mode="json_only"
+            ),
+            Traces(timestamp=now - timedelta(seconds=6), trace_id=trace_id, span_id=tool_id, parent_span_id=root_id, name="execute_tool get_weather", resources=resources, attributes={"gen_ai.tool.name": "get_weather"}, attribute_write_mode="json_only"),
+            Traces(timestamp=now - timedelta(seconds=4), trace_id=trace_id, span_id=second_llm_id, parent_span_id=root_id, name="chat gpt-4o", resources=resources, attributes={"gen_ai.request.model": "gpt-4o", "gen_ai.input.messages": second_input}, attribute_write_mode="json_only"),
+            Traces(timestamp=now - timedelta(seconds=2), trace_id=trace_id, span_id=third_llm_id, parent_span_id=root_id, name="chat gpt-4o", resources=resources, attributes={"gen_ai.request.model": "gpt-4o", "gen_ai.output.messages": "It is sunny in Bangalore."}, attribute_write_mode="json_only"),
+        ]
+    )
+
+    token = get_token(USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD)
+    response = requests.get(signoz.self.host_configs["8080"].get(f"/api/v1/traces/{trace_id}/thread"), headers={"Authorization": f"Bearer {token}"}, timeout=10)
+    assert response.status_code == HTTPStatus.OK, response.text
+
+    thread = response.json()["data"]
+    assert [span["span_id"] for span in thread["spans"]] == [first_llm_id, second_llm_id, third_llm_id]
+    assert "nextCursor" not in thread
+
+    first, input_only, output_only = thread["spans"]
+    assert first["time_unix"] == int((now - timedelta(seconds=8)).timestamp() * 1000)
+    assert first["attributes"]["gen_ai.input.messages"] == first_input
+    assert first["attributes"]["gen_ai.request.model"] == "gpt-4o"
+    assert first["attributes"]["gen_ai.output.messages"] == first_output
+    assert input_only["attributes"]["gen_ai.input.messages"] == second_input
+    assert "gen_ai.output.messages" not in input_only["attributes"]
+    assert "gen_ai.input.messages" not in output_only["attributes"]
+    assert output_only["attributes"]["gen_ai.output.messages"] == "It is sunny in Bangalore."
+
+
+def test_thread_paginates_with_cursor(
+    signoz: types.SigNoz,
+    create_user_admin: None,  # pylint: disable=unused-argument
+    get_token: Callable[[str, str], str],
+    insert_traces: Callable[[list[Traces]], None],
+) -> None:
+    now = datetime.now(tz=UTC).replace(microsecond=0)
+    trace_id = TraceIdGenerator.trace_id()
+    span_ids = [TraceIdGenerator.span_id() for _ in range(3)]
+    # identical timestamps on the last two exercise the span_id tie-break
+    timestamps = [now - timedelta(seconds=6), now - timedelta(seconds=3), now - timedelta(seconds=3)]
+    insert_traces(
+        [
+            Traces(timestamp=timestamp, trace_id=trace_id, span_id=span_id, name="chat gpt-4o", resources={"service.name": "tracedetail-thread-pages"}, attributes={"gen_ai.input.messages": json.dumps([{"role": "user", "content": span_id}])}, attribute_write_mode="json_only")
+            for span_id, timestamp in zip(span_ids, timestamps, strict=True)
+        ]
+    )
+    expected_order = [span_ids[0], *sorted(span_ids[1:])]
+
+    token = get_token(USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD)
+    url = signoz.self.host_configs["8080"].get(f"/api/v1/traces/{trace_id}/thread")
+    headers = {"Authorization": f"Bearer {token}"}
+
+    first_page = requests.get(url, params={"limit": 2}, headers=headers, timeout=10)
+    assert first_page.status_code == HTTPStatus.OK, first_page.text
+    first = first_page.json()["data"]
+    assert [span["span_id"] for span in first["spans"]] == expected_order[:2]
+    assert first["nextCursor"]
+
+    second_page = requests.get(url, params={"limit": 2, "cursor": first["nextCursor"]}, headers=headers, timeout=10)
+    assert second_page.status_code == HTTPStatus.OK, second_page.text
+    second = second_page.json()["data"]
+    assert [span["span_id"] for span in second["spans"]] == expected_order[2:]
+    assert "nextCursor" not in second
+
+
+def test_thread_without_messages_is_empty(
+    signoz: types.SigNoz,
+    create_user_admin: None,  # pylint: disable=unused-argument
+    get_token: Callable[[str, str], str],
+    insert_traces: Callable[[list[Traces]], None],
+) -> None:
+    trace_id = TraceIdGenerator.trace_id()
+    insert_traces([Traces(timestamp=datetime.now(tz=UTC) - timedelta(seconds=5), trace_id=trace_id, span_id=TraceIdGenerator.span_id(), name="GET /health", resources={"service.name": "tracedetail-thread-empty"}, attribute_write_mode="json_only")])
+
+    token = get_token(USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD)
+    response = requests.get(signoz.self.host_configs["8080"].get(f"/api/v1/traces/{trace_id}/thread"), headers={"Authorization": f"Bearer {token}"}, timeout=10)
+    assert response.status_code == HTTPStatus.OK, response.text
+    assert response.json()["data"] == {"spans": []}
+
+
+def test_thread_rejects_invalid_requests(
+    signoz: types.SigNoz,
+    create_user_admin: None,  # pylint: disable=unused-argument
+    get_token: Callable[[str, str], str],
+    insert_traces: Callable[[list[Traces]], None],
+) -> None:
+    trace_id = TraceIdGenerator.trace_id()
+    insert_traces([Traces(timestamp=datetime.now(tz=UTC) - timedelta(seconds=5), trace_id=trace_id, span_id=TraceIdGenerator.span_id(), name="chat gpt-4o", resources={"service.name": "tracedetail-thread-invalid"}, attributes={"gen_ai.input.messages": "hi"}, attribute_write_mode="json_only")])
+
+    token = get_token(USER_ADMIN_EMAIL, USER_ADMIN_PASSWORD)
+    headers = {"Authorization": f"Bearer {token}"}
+    url = signoz.self.host_configs["8080"].get(f"/api/v1/traces/{trace_id}/thread")
+
+    for params in ({"limit": -1}, {"limit": 1001}, {"cursor": "not-a-cursor"}):
+        response = requests.get(url, params=params, headers=headers, timeout=10)
+        assert response.status_code == HTTPStatus.BAD_REQUEST, f"{params}: {response.text}"
+
+    missing = requests.get(signoz.self.host_configs["8080"].get(f"/api/v1/traces/{TraceIdGenerator.trace_id()}/thread"), headers=headers, timeout=10)
+    assert missing.status_code == HTTPStatus.NOT_FOUND, missing.text