feat: observation history tracking and diff UI (#513)

* feat: add source facts token limits to consolidation and recall

- Add two new configurable (per-bank) parameters:
  - consolidation_source_facts_max_tokens: total token budget for source
    facts across all observations in the consolidation prompt (-1 = unlimited)
  - consolidation_source_facts_max_tokens_per_observation: per-observation
    cap so each observation gets a fair share of source facts (-1 = unlimited,
    default 256)
- Both are also exposed as recall API parameters via SourceFactsIncludeOptions
  (max_tokens and max_tokens_per_observation)
- Consolidation now uses resolve_full_config to respect bank-level overrides
- Improve consolidation prompt: temporal metadata (occurred_start=, | Involving:)
  is now clearly separated from observation text, with a concrete example showing
  the expected synthesis style and explicit rules not to copy raw fact lines
- Add tests for recall source facts capping and consolidation config forwarding
- Expose all three new fields in the control plane bank config UI
- Document new env vars in configuration.md
- Regenerate OpenAPI spec and all SDK clients

* fix: reorder observations UI fields and rename Label Groups to Entity Labels

* fix: revert Entities section title (only rename inner label)

* doc: add consolidation source facts and batch size fields to memory-banks docs

* feat: add observation history tracking and UI diff view

- Track observation changes over time in a JSONB history column,
  appending each update's previous state (text, tags, dates, sources)
  instead of overwriting
- Add HINDSIGHT_API_ENABLE_OBSERVATION_HISTORY config flag (default: true)
  to toggle history recording
- Expose history field in get_memory_unit for observations
- Fix observations/[modelId] route that was proxying to wrong endpoint
- Add History tab in observation modal and History section in panel,
  showing word-level and tag diffs between each change (newest first)
- Extract shared ObservationHistoryView component used by both modal and panel
- Add --random-port flag to start.sh to run multiple dev instances
- Scope Next.js distDir by port to prevent lock file collisions between instances
- Restyle consolidation pending badge (rounded-md with border) and add
  inline refresh button; fix loading flicker on data refresh

* feat: dedicated observation history endpoint with source facts diff

- Add GET /memories/{id}/history endpoint returning enriched history with
  resolved source fact texts and is_new flags per change
- Deprecate history field in GET /memories/{id} (always returns empty list)
- Reconstruct cumulative source facts per history entry by working backwards
  from current state, marking newly added facts with is_new
- Replace inline history panel with "View History" button opening modal
- History modal fetches from dedicated endpoint lazily on tab switch
- Timeline view now opens MemoryDetailModal instead of side panel
- History view uses prev/next navigation (left = older, right = newer)
- Fix --random-port: pass dynamic API_PORT as HINDSIGHT_CP_DATAPLANE_API_URL
  to control plane, preserving caller values over .env

hindsight-api/hindsight_api/api/http.py

@@ -2137,7 +2137,7 @@ def _register_routes(app: FastAPI):
     @app.get(
         "/v1/default/banks/{bank_id}/memories/{memory_id}",
         summary="Get memory unit",
-        description="Get a single memory unit by ID with all its metadata including entities and tags.",
+        description="Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.",
         operation_id="get_memory",
         tags=["Memory"],
     )
@@ -2167,6 +2167,39 @@ def _register_routes(app: FastAPI):
             logger.error(f"Error in /v1/default/banks/{bank_id}/memories/{memory_id}: {error_detail}")
             raise HTTPException(status_code=500, detail=str(e))
 
+    @app.get(
+        "/v1/default/banks/{bank_id}/memories/{memory_id}/history",
+        summary="Get observation history",
+        description="Get the full history of an observation, with each change's source facts resolved to their text.",
+        operation_id="get_observation_history",
+        tags=["Memory"],
+    )
+    async def api_get_observation_history(
+        bank_id: str,
+        memory_id: str,
+        request_context: RequestContext = Depends(get_request_context),
+    ):
+        """Get the history of a single observation by ID."""
+        try:
+            data = await app.state.memory.get_observation_history(
+                bank_id=bank_id,
+                memory_id=memory_id,
+                request_context=request_context,
+            )
+            if data is None:
+                raise HTTPException(status_code=404, detail=f"Memory unit '{memory_id}' not found")
+            return data
+        except OperationValidationError as e:
+            raise HTTPException(status_code=e.status_code, detail=e.reason)
+        except (AuthenticationError, HTTPException):
+            raise
+        except Exception as e:
+            import traceback
+
+            error_detail = f"{str(e)}\n\nTraceback:\n{traceback.format_exc()}"
+            logger.error(f"Error in /v1/default/banks/{bank_id}/memories/{memory_id}/history: {error_detail}")
+            raise HTTPException(status_code=500, detail=str(e))
+
     @app.post(
         "/v1/default/banks/{bank_id}/memories/recall",
         response_model=RecallResponse,

hindsight-api/hindsight_api/config.py

@@ -298,6 +298,7 @@ ENV_CONSOLIDATION_SOURCE_FACTS_MAX_TOKENS_PER_OBSERVATION = (
     "HINDSIGHT_API_CONSOLIDATION_SOURCE_FACTS_MAX_TOKENS_PER_OBSERVATION"
 )
 ENV_OBSERVATIONS_MISSION = "HINDSIGHT_API_OBSERVATIONS_MISSION"
+ENV_ENABLE_OBSERVATION_HISTORY = "HINDSIGHT_API_ENABLE_OBSERVATION_HISTORY"
 
 # Webhook configuration (global, static - server-level only)
 ENV_WEBHOOK_URL = "HINDSIGHT_API_WEBHOOK_URL"
@@ -449,6 +450,7 @@ DEFAULT_FILE_DELETE_AFTER_RETAIN = True  # Delete file bytes after retain (saves
 
 # Observations defaults (consolidated knowledge from facts)
 DEFAULT_ENABLE_OBSERVATIONS = True  # Observations enabled by default
+DEFAULT_ENABLE_OBSERVATION_HISTORY = True  # Observation history tracking enabled by default
 DEFAULT_CONSOLIDATION_BATCH_SIZE = 50  # Memories to load per batch (internal memory optimization)
 DEFAULT_CONSOLIDATION_LLM_BATCH_SIZE = 8  # Facts per LLM call (1 = no batching; >1 = batch mode)
 DEFAULT_CONSOLIDATION_MAX_TOKENS = 512  # Max tokens for recall when finding related observations
@@ -727,6 +729,7 @@ class HindsightConfig:
 
     # Observations settings (consolidated knowledge from facts)
     enable_observations: bool
+    enable_observation_history: bool
     consolidation_batch_size: int
     consolidation_llm_batch_size: int
     consolidation_max_tokens: int
@@ -1179,6 +1182,10 @@ class HindsightConfig:
             == "true",
             # Observations settings (consolidated knowledge from facts)
             enable_observations=os.getenv(ENV_ENABLE_OBSERVATIONS, str(DEFAULT_ENABLE_OBSERVATIONS)).lower() == "true",
+            enable_observation_history=os.getenv(
+                ENV_ENABLE_OBSERVATION_HISTORY, str(DEFAULT_ENABLE_OBSERVATION_HISTORY)
+            ).lower()
+            == "true",
             consolidation_batch_size=int(
                 os.getenv(ENV_CONSOLIDATION_BATCH_SIZE, str(DEFAULT_CONSOLIDATION_BATCH_SIZE))
             ),

hindsight-api/hindsight_api/engine/consolidation/consolidator.py

@@ -766,13 +766,17 @@ async def _execute_update_action(
         logger.debug(f"Update skipped: observation {observation_id} not found in recall results")
         return
 
-    history = [
+    from ...config import get_config
-        {
+
+    history_entry = {
         "previous_text": model.text,
+        "previous_tags": list(model.tags or []),
+        "previous_occurred_start": model.occurred_start,
+        "previous_occurred_end": model.occurred_end,
+        "previous_mentioned_at": model.mentioned_at,
         "changed_at": datetime.now(timezone.utc).isoformat(),
-            "source_memory_ids": [str(mid) for mid in source_memory_ids],
+        "new_source_memory_ids": [str(mid) for mid in source_memory_ids],
     }
-    ]
 
     source_ids = list(model.source_fact_ids or []) + source_memory_ids
 
@@ -787,13 +791,18 @@ async def _execute_update_action(
     if perf:
         perf.record_timing("embedding", time.time() - t0)
 
+    config = get_config()
+    history_clause = (
+        "history = COALESCE(history, '[]'::jsonb) || $3::jsonb," if config.enable_observation_history else ""
+    )
+
     t0 = time.time()
     await conn.execute(
         f"""
         UPDATE {fq_table("memory_units")}
         SET text = $1,
             embedding = $2::vector,
-            history = $3,
+            {history_clause}
             source_memory_ids = $4,
             proof_count = $5,
             tags = $10,
@@ -805,7 +814,7 @@ async def _execute_update_action(
         """,
         new_text,
         embedding_str,
-        json.dumps(history),
+        json.dumps([history_entry]),
         source_ids,
         len(source_ids),
         uuid.UUID(observation_id),

hindsight-api/hindsight_api/engine/memory_engine.py

@@ -4345,7 +4345,11 @@ class MemoryEngine(MemoryEngineInterface):
                 "observation_scopes": row["observation_scopes"] if row["observation_scopes"] else None,
             }
 
-            # For observations, include source_memory_ids and fetch source_memories
+            # For observations, include source_memory_ids
+            # history is deprecated here - use GET /memories/{id}/history instead
+            if row["fact_type"] == "observation":
+                result["history"] = []
+
             if row["fact_type"] == "observation" and row["source_memory_ids"]:
                 source_ids = row["source_memory_ids"]
                 result["source_memory_ids"] = [str(sid) for sid in source_ids]
@@ -4374,6 +4378,95 @@ class MemoryEngine(MemoryEngineInterface):
 
             return result
 
+    async def get_observation_history(
+        self,
+        bank_id: str,
+        memory_id: str,
+        request_context: "RequestContext",
+    ) -> list[dict] | None:
+        """
+        Get the history of an observation, with source facts resolved to their text.
+
+        Returns None if the memory is not found or is not an observation.
+        Returns a list of history entries (most recent first), each with source_facts resolved.
+        """
+        await self._authenticate_tenant(request_context)
+        if self._operation_validator:
+            from hindsight_api.extensions import BankReadContext
+
+            ctx = BankReadContext(bank_id=bank_id, operation="get_observation_history", request_context=request_context)
+            await self._validate_operation(self._operation_validator.validate_bank_read(ctx))
+        pool = await self._get_pool()
+        async with acquire_with_retry(pool) as conn:
+            row = await conn.fetchrow(
+                f"""
+                SELECT fact_type, history, source_memory_ids
+                FROM {fq_table("memory_units")}
+                WHERE id = $1 AND bank_id = $2
+                """,
+                uuid.UUID(memory_id),
+                bank_id,
+            )
+            if not row:
+                return None
+            if row["fact_type"] != "observation":
+                return []
+
+            raw_history = row["history"]
+            if isinstance(raw_history, str):
+                raw_history = json.loads(raw_history)
+            if not raw_history:
+                return []
+
+            # Collect all source memory IDs (current full set + all historical new ones)
+            current_source_ids: list[str] = [str(sid) for sid in (row["source_memory_ids"] or [])]
+            all_source_ids: set[uuid.UUID] = set(uuid.UUID(sid) for sid in current_source_ids)
+            for entry in raw_history:
+                for sid in entry.get("new_source_memory_ids", []):
+                    try:
+                        all_source_ids.add(uuid.UUID(sid))
+                    except (ValueError, AttributeError):
+                        pass
+
+            # Resolve all source memories in one query
+            source_map: dict[str, dict] = {}
+            if all_source_ids:
+                source_rows = await conn.fetch(
+                    f"""
+                    SELECT id, text, fact_type, context
+                    FROM {fq_table("memory_units")}
+                    WHERE id = ANY($1::uuid[])
+                    """,
+                    list(all_source_ids),
+                )
+                for r in source_rows:
+                    source_map[str(r["id"])] = {
+                        "id": str(r["id"]),
+                        "text": r["text"],
+                        "type": r["fact_type"],
+                        "context": r["context"] or None,
+                    }
+
+            # Reconstruct cumulative source IDs per change by working backwards from current state.
+            # Source IDs are only ever accumulated (never removed), so:
+            #   after_change_N = before_change_N + new_source_memory_ids_N
+            cumulative_ids: list[str] = list(current_source_ids)
+            enriched: list[dict] = []
+            for entry in reversed(raw_history):
+                new_ids_in_entry: set[str] = set(entry.get("new_source_memory_ids", []))
+                source_facts = []
+                for sid in cumulative_ids:
+                    fact = source_map.get(sid, {"id": sid, "text": None, "type": None, "context": None})
+                    source_facts.append({**fact, "is_new": sid in new_ids_in_entry})
+                enriched_entry = dict(entry)
+                enriched_entry["source_facts"] = source_facts
+                enriched.append(enriched_entry)
+                # Step back: remove the new IDs added by this change to get the prior state
+                cumulative_ids = [sid for sid in cumulative_ids if sid not in new_ids_in_entry]
+
+            enriched.reverse()
+            return enriched
+
     async def list_documents(
         self,
         bank_id: str,

hindsight-api/hindsight_api/main.py

@@ -276,6 +276,7 @@ def main():
             enable_file_upload_api=config.enable_file_upload_api,
             file_delete_after_retain=config.file_delete_after_retain,
             enable_observations=config.enable_observations,
+            enable_observation_history=config.enable_observation_history,
             consolidation_batch_size=config.consolidation_batch_size,
             consolidation_llm_batch_size=config.consolidation_llm_batch_size,
             consolidation_max_tokens=config.consolidation_max_tokens,

hindsight-clients/go/api/openapi.yaml

@@ -210,8 +210,9 @@ paths:
       - Memory
   /v1/default/banks/{bank_id}/memories/{memory_id}:
     get:
-      description: Get a single memory unit by ID with all its metadata including
+      description: "Get a single memory unit by ID with all its metadata including\
-        entities and tags.
+        \ entities and tags. Note: the 'history' field is deprecated and always returns\
+        \ an empty list - use GET /memories/{memory_id}/history instead."
       operationId: get_memory
       parameters:
       - explode: false
@@ -253,6 +254,51 @@ paths:
       summary: Get memory unit
       tags:
       - Memory
+  /v1/default/banks/{bank_id}/memories/{memory_id}/history:
+    get:
+      description: "Get the full history of an observation, with each change's source\
+        \ facts resolved to their text."
+      operationId: get_observation_history
+      parameters:
+      - explode: false
+        in: path
+        name: bank_id
+        required: true
+        schema:
+          title: Bank Id
+          type: string
+        style: simple
+      - explode: false
+        in: path
+        name: memory_id
+        required: true
+        schema:
+          title: Memory Id
+          type: string
+        style: simple
+      - explode: false
+        in: header
+        name: authorization
+        required: false
+        schema:
+          nullable: true
+          type: string
+        style: simple
+      responses:
+        "200":
+          content:
+            application/json:
+              schema: {}
+          description: Successful Response
+        "422":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/HTTPValidationError'
+          description: Validation Error
+      summary: Get observation history
+      tags:
+      - Memory
   /v1/default/banks/{bank_id}/memories/recall:
     post:
       description: |-

hindsight-clients/go/api_memory.go

@@ -483,7 +483,7 @@ func (r ApiGetMemoryRequest) Execute() (interface{}, *http.Response, error) {
 /*
 GetMemory Get memory unit
 
-Get a single memory unit by ID with all its metadata including entities and tags.
+Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.
 
  @param ctx context.Context - for authentication, logging, cancellation, deadlines, tracing, etc. Passed from http.Request or context.Background().
  @param bankId
@@ -589,6 +589,132 @@ func (a *MemoryAPIService) GetMemoryExecute(r ApiGetMemoryRequest) (interface{},
 	return localVarReturnValue, localVarHTTPResponse, nil
 }
 
+type ApiGetObservationHistoryRequest struct {
+	ctx context.Context
+	ApiService *MemoryAPIService
+	bankId string
+	memoryId string
+	authorization *string
+}
+
+func (r ApiGetObservationHistoryRequest) Authorization(authorization string) ApiGetObservationHistoryRequest {
+	r.authorization = &authorization
+	return r
+}
+
+func (r ApiGetObservationHistoryRequest) Execute() (interface{}, *http.Response, error) {
+	return r.ApiService.GetObservationHistoryExecute(r)
+}
+
+/*
+GetObservationHistory Get observation history
+
+Get the full history of an observation, with each change's source facts resolved to their text.
+
+ @param ctx context.Context - for authentication, logging, cancellation, deadlines, tracing, etc. Passed from http.Request or context.Background().
+ @param bankId
+ @param memoryId
+ @return ApiGetObservationHistoryRequest
+*/
+func (a *MemoryAPIService) GetObservationHistory(ctx context.Context, bankId string, memoryId string) ApiGetObservationHistoryRequest {
+	return ApiGetObservationHistoryRequest{
+		ApiService: a,
+		ctx: ctx,
+		bankId: bankId,
+		memoryId: memoryId,
+	}
+}
+
+// Execute executes the request
+//  @return interface{}
+func (a *MemoryAPIService) GetObservationHistoryExecute(r ApiGetObservationHistoryRequest) (interface{}, *http.Response, error) {
+	var (
+		localVarHTTPMethod   = http.MethodGet
+		localVarPostBody     interface{}
+		formFiles            []formFile
+		localVarReturnValue  interface{}
+	)
+
+	localBasePath, err := a.client.cfg.ServerURLWithContext(r.ctx, "MemoryAPIService.GetObservationHistory")
+	if err != nil {
+		return localVarReturnValue, nil, &GenericOpenAPIError{error: err.Error()}
+	}
+
+	localVarPath := localBasePath + "/v1/default/banks/{bank_id}/memories/{memory_id}/history"
+	localVarPath = strings.Replace(localVarPath, "{"+"bank_id"+"}", url.PathEscape(parameterValueToString(r.bankId, "bankId")), -1)
+	localVarPath = strings.Replace(localVarPath, "{"+"memory_id"+"}", url.PathEscape(parameterValueToString(r.memoryId, "memoryId")), -1)
+
+	localVarHeaderParams := make(map[string]string)
+	localVarQueryParams := url.Values{}
+	localVarFormParams := url.Values{}
+
+	// to determine the Content-Type header
+	localVarHTTPContentTypes := []string{}
+
+	// set Content-Type header
+	localVarHTTPContentType := selectHeaderContentType(localVarHTTPContentTypes)
+	if localVarHTTPContentType != "" {
+		localVarHeaderParams["Content-Type"] = localVarHTTPContentType
+	}
+
+	// to determine the Accept header
+	localVarHTTPHeaderAccepts := []string{"application/json"}
+
+	// set Accept header
+	localVarHTTPHeaderAccept := selectHeaderAccept(localVarHTTPHeaderAccepts)
+	if localVarHTTPHeaderAccept != "" {
+		localVarHeaderParams["Accept"] = localVarHTTPHeaderAccept
+	}
+	if r.authorization != nil {
+		parameterAddToHeaderOrQuery(localVarHeaderParams, "authorization", r.authorization, "simple", "")
+	}
+	req, err := a.client.prepareRequest(r.ctx, localVarPath, localVarHTTPMethod, localVarPostBody, localVarHeaderParams, localVarQueryParams, localVarFormParams, formFiles)
+	if err != nil {
+		return localVarReturnValue, nil, err
+	}
+
+	localVarHTTPResponse, err := a.client.callAPI(req)
+	if err != nil || localVarHTTPResponse == nil {
+		return localVarReturnValue, localVarHTTPResponse, err
+	}
+
+	localVarBody, err := io.ReadAll(localVarHTTPResponse.Body)
+	localVarHTTPResponse.Body.Close()
+	localVarHTTPResponse.Body = io.NopCloser(bytes.NewBuffer(localVarBody))
+	if err != nil {
+		return localVarReturnValue, localVarHTTPResponse, err
+	}
+
+	if localVarHTTPResponse.StatusCode >= 300 {
+		newErr := &GenericOpenAPIError{
+			body:  localVarBody,
+			error: localVarHTTPResponse.Status,
+		}
+		if localVarHTTPResponse.StatusCode == 422 {
+			var v HTTPValidationError
+			err = a.client.decode(&v, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
+			if err != nil {
+				newErr.error = err.Error()
+				return localVarReturnValue, localVarHTTPResponse, newErr
+			}
+					newErr.error = formatErrorMessage(localVarHTTPResponse.Status, &v)
+					newErr.model = v
+		}
+		return localVarReturnValue, localVarHTTPResponse, newErr
+	}
+
+	err = a.client.decode(&localVarReturnValue, localVarBody, localVarHTTPResponse.Header.Get("Content-Type"))
+	if err != nil {
+		newErr := &GenericOpenAPIError{
+			body:  localVarBody,
+			error: err.Error(),
+		}
+		return localVarReturnValue, localVarHTTPResponse, newErr
+	}
+
+	return localVarReturnValue, localVarHTTPResponse, nil
+}
+
 type ApiListMemoriesRequest struct {
 	ctx context.Context
 	ApiService *MemoryAPIService

hindsight-clients/python/hindsight_client_api/api/memory_api.py

@@ -1022,7 +1022,7 @@ class MemoryApi:
     ) -> object:
         """Get memory unit
 
-        Get a single memory unit by ID with all its metadata including entities and tags.
+        Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.
 
         :param bank_id: (required)
         :type bank_id: str
@@ -1098,7 +1098,7 @@ class MemoryApi:
     ) -> ApiResponse[object]:
         """Get memory unit
 
-        Get a single memory unit by ID with all its metadata including entities and tags.
+        Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.
 
         :param bank_id: (required)
         :type bank_id: str
@@ -1174,7 +1174,7 @@ class MemoryApi:
     ) -> RESTResponseType:
         """Get memory unit
 
-        Get a single memory unit by ID with all its metadata including entities and tags.
+        Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.
 
         :param bank_id: (required)
         :type bank_id: str
@@ -1294,6 +1294,299 @@ class MemoryApi:
 
 
 
+    @validate_call
+    async def get_observation_history(
+        self,
+        bank_id: StrictStr,
+        memory_id: StrictStr,
+        authorization: Optional[StrictStr] = None,
+        _request_timeout: Union[
+            None,
+            Annotated[StrictFloat, Field(gt=0)],
+            Tuple[
+                Annotated[StrictFloat, Field(gt=0)],
+                Annotated[StrictFloat, Field(gt=0)]
+            ]
+        ] = None,
+        _request_auth: Optional[Dict[StrictStr, Any]] = None,
+        _content_type: Optional[StrictStr] = None,
+        _headers: Optional[Dict[StrictStr, Any]] = None,
+        _host_index: Annotated[StrictInt, Field(ge=0, le=0)] = 0,
+    ) -> object:
+        """Get observation history
+
+        Get the full history of an observation, with each change's source facts resolved to their text.
+
+        :param bank_id: (required)
+        :type bank_id: str
+        :param memory_id: (required)
+        :type memory_id: str
+        :param authorization:
+        :type authorization: str
+        :param _request_timeout: timeout setting for this request. If one
+                                 number provided, it will be total request
+                                 timeout. It can also be a pair (tuple) of
+                                 (connection, read) timeouts.
+        :type _request_timeout: int, tuple(int, int), optional
+        :param _request_auth: set to override the auth_settings for an a single
+                              request; this effectively ignores the
+                              authentication in the spec for a single request.
+        :type _request_auth: dict, optional
+        :param _content_type: force content-type for the request.
+        :type _content_type: str, Optional
+        :param _headers: set to override the headers for a single
+                         request; this effectively ignores the headers
+                         in the spec for a single request.
+        :type _headers: dict, optional
+        :param _host_index: set to override the host_index for a single
+                            request; this effectively ignores the host_index
+                            in the spec for a single request.
+        :type _host_index: int, optional
+        :return: Returns the result object.
+        """ # noqa: E501
+
+        _param = self._get_observation_history_serialize(
+            bank_id=bank_id,
+            memory_id=memory_id,
+            authorization=authorization,
+            _request_auth=_request_auth,
+            _content_type=_content_type,
+            _headers=_headers,
+            _host_index=_host_index
+        )
+
+        _response_types_map: Dict[str, Optional[str]] = {
+            '200': "object",
+            '422': "HTTPValidationError",
+        }
+        response_data = await self.api_client.call_api(
+            *_param,
+            _request_timeout=_request_timeout
+        )
+        await response_data.read()
+        return self.api_client.response_deserialize(
+            response_data=response_data,
+            response_types_map=_response_types_map,
+        ).data
+
+
+    @validate_call
+    async def get_observation_history_with_http_info(
+        self,
+        bank_id: StrictStr,
+        memory_id: StrictStr,
+        authorization: Optional[StrictStr] = None,
+        _request_timeout: Union[
+            None,
+            Annotated[StrictFloat, Field(gt=0)],
+            Tuple[
+                Annotated[StrictFloat, Field(gt=0)],
+                Annotated[StrictFloat, Field(gt=0)]
+            ]
+        ] = None,
+        _request_auth: Optional[Dict[StrictStr, Any]] = None,
+        _content_type: Optional[StrictStr] = None,
+        _headers: Optional[Dict[StrictStr, Any]] = None,
+        _host_index: Annotated[StrictInt, Field(ge=0, le=0)] = 0,
+    ) -> ApiResponse[object]:
+        """Get observation history
+
+        Get the full history of an observation, with each change's source facts resolved to their text.
+
+        :param bank_id: (required)
+        :type bank_id: str
+        :param memory_id: (required)
+        :type memory_id: str
+        :param authorization:
+        :type authorization: str
+        :param _request_timeout: timeout setting for this request. If one
+                                 number provided, it will be total request
+                                 timeout. It can also be a pair (tuple) of
+                                 (connection, read) timeouts.
+        :type _request_timeout: int, tuple(int, int), optional
+        :param _request_auth: set to override the auth_settings for an a single
+                              request; this effectively ignores the
+                              authentication in the spec for a single request.
+        :type _request_auth: dict, optional
+        :param _content_type: force content-type for the request.
+        :type _content_type: str, Optional
+        :param _headers: set to override the headers for a single
+                         request; this effectively ignores the headers
+                         in the spec for a single request.
+        :type _headers: dict, optional
+        :param _host_index: set to override the host_index for a single
+                            request; this effectively ignores the host_index
+                            in the spec for a single request.
+        :type _host_index: int, optional
+        :return: Returns the result object.
+        """ # noqa: E501
+
+        _param = self._get_observation_history_serialize(
+            bank_id=bank_id,
+            memory_id=memory_id,
+            authorization=authorization,
+            _request_auth=_request_auth,
+            _content_type=_content_type,
+            _headers=_headers,
+            _host_index=_host_index
+        )
+
+        _response_types_map: Dict[str, Optional[str]] = {
+            '200': "object",
+            '422': "HTTPValidationError",
+        }
+        response_data = await self.api_client.call_api(
+            *_param,
+            _request_timeout=_request_timeout
+        )
+        await response_data.read()
+        return self.api_client.response_deserialize(
+            response_data=response_data,
+            response_types_map=_response_types_map,
+        )
+
+
+    @validate_call
+    async def get_observation_history_without_preload_content(
+        self,
+        bank_id: StrictStr,
+        memory_id: StrictStr,
+        authorization: Optional[StrictStr] = None,
+        _request_timeout: Union[
+            None,
+            Annotated[StrictFloat, Field(gt=0)],
+            Tuple[
+                Annotated[StrictFloat, Field(gt=0)],
+                Annotated[StrictFloat, Field(gt=0)]
+            ]
+        ] = None,
+        _request_auth: Optional[Dict[StrictStr, Any]] = None,
+        _content_type: Optional[StrictStr] = None,
+        _headers: Optional[Dict[StrictStr, Any]] = None,
+        _host_index: Annotated[StrictInt, Field(ge=0, le=0)] = 0,
+    ) -> RESTResponseType:
+        """Get observation history
+
+        Get the full history of an observation, with each change's source facts resolved to their text.
+
+        :param bank_id: (required)
+        :type bank_id: str
+        :param memory_id: (required)
+        :type memory_id: str
+        :param authorization:
+        :type authorization: str
+        :param _request_timeout: timeout setting for this request. If one
+                                 number provided, it will be total request
+                                 timeout. It can also be a pair (tuple) of
+                                 (connection, read) timeouts.
+        :type _request_timeout: int, tuple(int, int), optional
+        :param _request_auth: set to override the auth_settings for an a single
+                              request; this effectively ignores the
+                              authentication in the spec for a single request.
+        :type _request_auth: dict, optional
+        :param _content_type: force content-type for the request.
+        :type _content_type: str, Optional
+        :param _headers: set to override the headers for a single
+                         request; this effectively ignores the headers
+                         in the spec for a single request.
+        :type _headers: dict, optional
+        :param _host_index: set to override the host_index for a single
+                            request; this effectively ignores the host_index
+                            in the spec for a single request.
+        :type _host_index: int, optional
+        :return: Returns the result object.
+        """ # noqa: E501
+
+        _param = self._get_observation_history_serialize(
+            bank_id=bank_id,
+            memory_id=memory_id,
+            authorization=authorization,
+            _request_auth=_request_auth,
+            _content_type=_content_type,
+            _headers=_headers,
+            _host_index=_host_index
+        )
+
+        _response_types_map: Dict[str, Optional[str]] = {
+            '200': "object",
+            '422': "HTTPValidationError",
+        }
+        response_data = await self.api_client.call_api(
+            *_param,
+            _request_timeout=_request_timeout
+        )
+        return response_data.response
+
+
+    def _get_observation_history_serialize(
+        self,
+        bank_id,
+        memory_id,
+        authorization,
+        _request_auth,
+        _content_type,
+        _headers,
+        _host_index,
+    ) -> RequestSerialized:
+
+        _host = None
+
+        _collection_formats: Dict[str, str] = {
+        }
+
+        _path_params: Dict[str, str] = {}
+        _query_params: List[Tuple[str, str]] = []
+        _header_params: Dict[str, Optional[str]] = _headers or {}
+        _form_params: List[Tuple[str, str]] = []
+        _files: Dict[
+            str, Union[str, bytes, List[str], List[bytes], List[Tuple[str, bytes]]]
+        ] = {}
+        _body_params: Optional[bytes] = None
+
+        # process the path parameters
+        if bank_id is not None:
+            _path_params['bank_id'] = bank_id
+        if memory_id is not None:
+            _path_params['memory_id'] = memory_id
+        # process the query parameters
+        # process the header parameters
+        if authorization is not None:
+            _header_params['authorization'] = authorization
+        # process the form parameters
+        # process the body parameter
+
+
+        # set the HTTP header `Accept`
+        if 'Accept' not in _header_params:
+            _header_params['Accept'] = self.api_client.select_header_accept(
+                [
+                    'application/json'
+                ]
+            )
+
+
+        # authentication setting
+        _auth_settings: List[str] = [
+        ]
+
+        return self.api_client.param_serialize(
+            method='GET',
+            resource_path='/v1/default/banks/{bank_id}/memories/{memory_id}/history',
+            path_params=_path_params,
+            query_params=_query_params,
+            header_params=_header_params,
+            body=_body_params,
+            post_params=_form_params,
+            files=_files,
+            auth_settings=_auth_settings,
+            collection_formats=_collection_formats,
+            _host=_host,
+            _request_auth=_request_auth
+        )
+
+
+
+
     @validate_call
     async def list_memories(
         self,

hindsight-clients/typescript/generated/sdk.gen.ts

@@ -83,6 +83,9 @@ import type {
   GetMentalModelData,
   GetMentalModelErrors,
   GetMentalModelResponses,
+  GetObservationHistoryData,
+  GetObservationHistoryErrors,
+  GetObservationHistoryResponses,
   GetOperationStatusData,
   GetOperationStatusErrors,
   GetOperationStatusResponses,
@@ -252,7 +255,7 @@ export const listMemories = <ThrowOnError extends boolean = false>(
 /**
  * Get memory unit
  *
- * Get a single memory unit by ID with all its metadata including entities and tags.
+ * Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.
  */
 export const getMemory = <ThrowOnError extends boolean = false>(
   options: Options<GetMemoryData, ThrowOnError>,
@@ -263,6 +266,23 @@ export const getMemory = <ThrowOnError extends boolean = false>(
     ThrowOnError
   >({ url: "/v1/default/banks/{bank_id}/memories/{memory_id}", ...options });
 
+/**
+ * Get observation history
+ *
+ * Get the full history of an observation, with each change's source facts resolved to their text.
+ */
+export const getObservationHistory = <ThrowOnError extends boolean = false>(
+  options: Options<GetObservationHistoryData, ThrowOnError>,
+) =>
+  (options.client ?? client).get<
+    GetObservationHistoryResponses,
+    GetObservationHistoryErrors,
+    ThrowOnError
+  >({
+    url: "/v1/default/banks/{bank_id}/memories/{memory_id}/history",
+    ...options,
+  });
+
 /**
  * Recall memory
  *

hindsight-clients/typescript/generated/types.gen.ts

@@ -2549,6 +2549,45 @@ export type GetMemoryResponses = {
   200: unknown;
 };
 
+export type GetObservationHistoryData = {
+  body?: never;
+  headers?: {
+    /**
+     * Authorization
+     */
+    authorization?: string | null;
+  };
+  path: {
+    /**
+     * Bank Id
+     */
+    bank_id: string;
+    /**
+     * Memory Id
+     */
+    memory_id: string;
+  };
+  query?: never;
+  url: "/v1/default/banks/{bank_id}/memories/{memory_id}/history";
+};
+
+export type GetObservationHistoryErrors = {
+  /**
+   * Validation Error
+   */
+  422: HttpValidationError;
+};
+
+export type GetObservationHistoryError =
+  GetObservationHistoryErrors[keyof GetObservationHistoryErrors];
+
+export type GetObservationHistoryResponses = {
+  /**
+   * Successful Response
+   */
+  200: unknown;
+};
+
 export type RecallMemoriesData = {
   body: RecallRequest;
   headers?: {

hindsight-control-plane/.gitignore

@@ -10,6 +10,7 @@
 
 # next.js
 /.next/
+/.next-*/
 /out/
 
 # production

hindsight-control-plane/next.config.ts

@@ -3,8 +3,14 @@ import path from "path";
 
 const basePath = process.env.NEXT_PUBLIC_BASE_PATH || '';
 
+// Use a port-scoped distDir so multiple dev instances don't collide on the lock file
+const distDir = process.env.PORT && process.env.PORT !== '9999'
+  ? `.next-${process.env.PORT}`
+  : '.next';
+
 const nextConfig: NextConfig = {
   output: 'standalone',
+  distDir,
   basePath: basePath,
   assetPrefix: basePath,
   // Disable request logging in production

hindsight-control-plane/src/app/api/banks/[bankId]/observations/[modelId]/route.ts

@@ -13,17 +13,14 @@ export async function GET(
     }
 
     const response = await fetch(
-      `${DATAPLANE_URL}/v1/default/banks/${bankId}/mental-models/${modelId}`,
+      `${DATAPLANE_URL}/v1/default/banks/${bankId}/memories/${modelId}`,
       { method: "GET", headers: getDataplaneHeaders() }
     );
 
     if (!response.ok) {
       const errorText = await response.text();
-      console.error("API error getting mental model:", errorText);
+      console.error("API error getting observation:", errorText);
-      return NextResponse.json(
+      return NextResponse.json({ error: "Failed to get observation" }, { status: response.status });
-        { error: "Failed to get mental model" },
-        { status: response.status }
-      );
     }
 
     const data = await response.json();

hindsight-control-plane/src/app/api/memories/[memoryId]/history/route.ts

@@ -0,0 +1,38 @@
+import { NextRequest, NextResponse } from "next/server";
+import { DATAPLANE_URL, getDataplaneHeaders } from "@/lib/hindsight-client";
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ memoryId: string }> }
+) {
+  try {
+    const { memoryId } = await params;
+    const searchParams = request.nextUrl.searchParams;
+    const bankId = searchParams.get("bank_id");
+
+    if (!bankId) {
+      return NextResponse.json({ error: "bank_id is required" }, { status: 400 });
+    }
+
+    const response = await fetch(
+      `${DATAPLANE_URL}/v1/default/banks/${bankId}/memories/${memoryId}/history`,
+      {
+        method: "GET",
+        headers: getDataplaneHeaders({ "Content-Type": "application/json" }),
+      }
+    );
+
+    if (!response.ok) {
+      if (response.status === 404) {
+        return NextResponse.json({ error: "Memory not found" }, { status: 404 });
+      }
+      throw new Error(`API returned ${response.status}`);
+    }
+
+    const data = await response.json();
+    return NextResponse.json(data, { status: 200 });
+  } catch (error) {
+    console.error("Error fetching observation history:", error);
+    return NextResponse.json({ error: "Failed to fetch observation history" }, { status: 500 });
+  }
+}

hindsight-control-plane/src/components/data-view.tsx

@@ -280,7 +280,7 @@ export function DataView({ factType }: DataViewProps) {
 
   return (
     <div>
-      {loading ? (
+      {loading && !data ? (
         <div className="text-center py-12">
           <RefreshCw className="w-8 h-8 mx-auto mb-3 text-muted-foreground animate-spin" />
           <p className="text-muted-foreground">Loading memories...</p>
@@ -370,11 +370,11 @@ export function DataView({ factType }: DataViewProps) {
 
               {/* Consolidation status for observations */}
               {factType === "observation" && consolidationStatus && (
-                <div
+                <span
-                  className={`flex items-center gap-1.5 px-2.5 py-1 rounded-full text-xs font-medium ${
+                  className={`inline-flex items-center gap-1 px-2 py-0.5 rounded-md text-xs font-medium border ${
                     consolidationStatus.pending_consolidation === 0
-                      ? "bg-emerald-500/10 text-emerald-600 dark:text-emerald-400 border border-emerald-500/20"
+                      ? "bg-green-500/10 text-green-700 dark:text-green-400 border-green-500/20"
-                      : "bg-amber-500/10 text-amber-600 dark:text-amber-400 border border-amber-500/20"
+                      : "bg-amber-500/10 text-amber-700 dark:text-amber-400 border-amber-500/20"
                   }`}
                   title={
                     consolidationStatus.pending_consolidation === 0
@@ -391,9 +391,23 @@ export function DataView({ factType }: DataViewProps) {
                     <>
                       <Clock className="w-3 h-3" />
                       {consolidationStatus.pending_consolidation} Pending
+                      <button
+                        onClick={() =>
+                          loadData(
+                            fetchLimit,
+                            searchQuery || undefined,
+                            tagFilters.length > 0 ? tagFilters : undefined
+                          )
+                        }
+                        disabled={loading}
+                        className="ml-0.5 opacity-70 hover:opacity-100 disabled:opacity-40 transition-opacity"
+                        title="Refresh observations"
+                      >
+                        <RefreshCw className={`w-3 h-3 ${loading ? "animate-spin" : ""}`} />
+                      </button>
                     </>
                   )}
-                </div>
+                </span>
               )}
             </div>
             <div className="flex items-center gap-2 bg-muted rounded-lg p-1">
@@ -874,6 +888,7 @@ export function DataView({ factType }: DataViewProps) {
               data={data}
               filteredRows={filteredTableRows}
               bankId={currentBank || undefined}
+              onMemoryClick={(id) => setModalMemoryId(id)}
             />
           )}
         </>
@@ -899,12 +914,13 @@ function TimelineView({
   data,
   filteredRows,
   bankId,
+  onMemoryClick,
 }: {
   data: any;
   filteredRows: any[];
   bankId?: string;
+  onMemoryClick: (id: string) => void;
 }) {
-  const [selectedItem, setSelectedItem] = useState<any>(null);
   const [granularity, setGranularity] = useState<Granularity>("month");
   const [currentIndex, setCurrentIndex] = useState(0);
   const timelineRef = useRef<HTMLDivElement>(null);
@@ -1182,10 +1198,8 @@ function TimelineView({
                 {group.items.map((item: any, idx: number) => (
                   <div
                     key={item.id || idx}
-                    onClick={() => setSelectedItem(item)}
+                    onClick={() => onMemoryClick(item.id)}
-                    className={`flex items-start cursor-pointer group ${
+                    className={`flex items-start cursor-pointer group ${"hover:opacity-80"}`}
-                      selectedItem?.id === item.id ? "opacity-100" : "hover:opacity-80"
-                    }`}
                   >
                     {/* Date & Time */}
                     <div className="w-[60px] text-right pr-3 pt-1 flex-shrink-0">
@@ -1200,21 +1214,13 @@ function TimelineView({
                     {/* Connector dot */}
                     <div className="flex-shrink-0 pt-2">
                       <div
-                        className={`w-1.5 h-1.5 rounded-full z-10 ${
+                        className={`w-1.5 h-1.5 rounded-full z-10 ${"bg-muted-foreground/50 group-hover:bg-primary"}`}
-                          selectedItem?.id === item.id
-                            ? "bg-primary"
-                            : "bg-muted-foreground/50 group-hover:bg-primary"
-                        }`}
                       />
                     </div>
 
                     {/* Card */}
                     <div
-                      className={`ml-3 flex-1 p-2 rounded border transition-colors ${
+                      className={`ml-3 flex-1 p-2 rounded border transition-colors ${"bg-card border-border hover:border-primary/50"}`}
-                        selectedItem?.id === item.id
-                          ? "bg-primary/10 border-primary"
-                          : "bg-card border-border hover:border-primary/50"
-                      }`}
                     >
                       <p className="text-xs text-foreground line-clamp-2 leading-relaxed">
                         {item.text}
@@ -1252,18 +1258,6 @@ function TimelineView({
           ))}
         </div>
       </div>
-
-      {/* Detail Panel - Fixed on Right */}
-      {selectedItem && (
-        <div className="fixed right-0 top-0 h-screen w-[420px] bg-card border-l-2 border-primary shadow-2xl z-50 overflow-y-auto animate-in slide-in-from-right duration-300 ease-out">
-          <MemoryDetailPanel
-            memory={selectedItem}
-            onClose={() => setSelectedItem(null)}
-            inPanel
-            bankId={bankId}
-          />
-        </div>
-      )}
     </div>
   );
 }

hindsight-control-plane/src/components/memory-detail-modal.tsx

@@ -5,9 +5,10 @@ import { client } from "@/lib/api";
 import { useBank } from "@/lib/bank-context";
 import { Dialog, DialogContent, DialogHeader, DialogTitle } from "@/components/ui/dialog";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
-import { Loader2, Calendar, Users, FileText, Layers, Tag } from "lucide-react";
+import { Loader2, Calendar, Users, FileText, Layers, Tag, History } from "lucide-react";
 import { TagList } from "@/components/ui/tag-list";
 import { Button } from "@/components/ui/button";
+import { ObservationHistoryView, type HistoryEntry } from "@/components/observation-history-view";
 
 interface SourceMemory {
   id: string;
@@ -38,14 +39,15 @@ interface MemoryDetail {
 interface MemoryDetailModalProps {
   memoryId: string | null;
   onClose: () => void;
+  initialTab?: string;
 }
 
-export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps) {
+export function MemoryDetailModal({ memoryId, onClose, initialTab }: MemoryDetailModalProps) {
   const { currentBank } = useBank();
   const [memory, setMemory] = useState<MemoryDetail | null>(null);
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState<string | null>(null);
-  const [activeTab, setActiveTab] = useState("memory");
+  const [activeTab, setActiveTab] = useState(initialTab ?? "memory");
 
   // Document and chunk data
   const [document, setDocument] = useState<any>(null);
@@ -53,6 +55,10 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
   const [loadingDocument, setLoadingDocument] = useState(false);
   const [loadingChunk, setLoadingChunk] = useState(false);
 
+  // History data (fetched lazily from dedicated endpoint)
+  const [history, setHistory] = useState<HistoryEntry[] | null>(null);
+  const [loadingHistory, setLoadingHistory] = useState(false);
+
   // Source memory modal (for viewing source memories of observations)
   const [sourceMemoryModalId, setSourceMemoryModalId] = useState<string | null>(null);
 
@@ -66,7 +72,8 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
       setMemory(null);
       setDocument(null);
       setChunk(null);
-      setActiveTab("memory");
+      setHistory(null);
+      setActiveTab(initialTab ?? "memory");
 
       try {
         const data = await client.getMemory(memoryId, currentBank);
@@ -82,6 +89,33 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
     loadMemory();
   }, [memoryId, currentBank]);
 
+  // Load history lazily when history tab is selected
+  useEffect(() => {
+    if (
+      activeTab !== "history" ||
+      !memory ||
+      memory.type !== "observation" ||
+      !currentBank ||
+      history !== null
+    )
+      return;
+
+    const loadHistory = async () => {
+      setLoadingHistory(true);
+      try {
+        const data = await client.getObservationHistory(memory.id, currentBank);
+        setHistory(data);
+      } catch (err) {
+        console.error("Error loading history:", err);
+        setHistory([]);
+      } finally {
+        setLoadingHistory(false);
+      }
+    };
+
+    loadHistory();
+  }, [activeTab, memory, currentBank, history]);
+
   // Load document when tab is selected
   useEffect(() => {
     if (activeTab !== "document" || !memory?.document_id || !currentBank || document) return;
@@ -152,11 +186,31 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
             </div>
           ) : memory ? (
             isObservation ? (
-              /* Observation view - no tabs since chunk/document don't apply */
+              /* Observation view - tabs for Info and History */
-              <div className="flex-1 overflow-y-auto space-y-4">
+              <Tabs
+                value={activeTab}
+                onValueChange={setActiveTab}
+                className="flex-1 flex flex-col overflow-hidden"
+              >
+                <TabsList className="grid w-full grid-cols-2">
+                  <TabsTrigger value="memory" className="flex items-center gap-1.5">
+                    <FileText className="w-3.5 h-3.5" />
+                    Observation
+                  </TabsTrigger>
+                  <TabsTrigger value="history" className="flex items-center gap-1.5">
+                    <History className="w-3.5 h-3.5" />
+                    History
+                    {history && history.length > 0 ? ` (${history.length})` : ""}
+                  </TabsTrigger>
+                </TabsList>
+
+                <div className="flex-1 overflow-y-auto mt-4">
+                  <TabsContent value="memory" className="mt-0 space-y-4">
                     {/* Text */}
                     <div>
-                  <div className="text-xs font-bold text-muted-foreground uppercase mb-2">Text</div>
+                      <div className="text-xs font-bold text-muted-foreground uppercase mb-2">
+                        Text
+                      </div>
                       <p className="text-sm text-foreground leading-relaxed">{memory.text}</p>
                     </div>
 
@@ -170,7 +224,8 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
                           <Calendar className="h-4 w-4 text-muted-foreground flex-shrink-0" />
                           <span>
                             {new Date(memory.occurred_start).toLocaleString()}
-                        {memory.occurred_end && memory.occurred_end !== memory.occurred_start && (
+                            {memory.occurred_end &&
+                              memory.occurred_end !== memory.occurred_start && (
                                 <>
                                   <span className="text-muted-foreground mx-1">→</span>
                                   {new Date(memory.occurred_end).toLocaleString()}
@@ -307,7 +362,32 @@ export function MemoryDetailModal({ memoryId, onClose }: MemoryDetailModalProps)
                         {memory.id}
                       </code>
                     </div>
+                  </TabsContent>
+
+                  <TabsContent value="history" className="mt-0">
+                    {loadingHistory ? (
+                      <div className="flex items-center justify-center py-12">
+                        <Loader2 className="w-6 h-6 animate-spin text-muted-foreground" />
                       </div>
+                    ) : history && history.length > 0 ? (
+                      <ObservationHistoryView
+                        history={history}
+                        current={{
+                          text: memory.text,
+                          tags: memory.tags,
+                          occurred_start: memory.occurred_start,
+                          occurred_end: memory.occurred_end,
+                          mentioned_at: memory.mentioned_at,
+                        }}
+                      />
+                    ) : (
+                      <p className="text-sm text-muted-foreground italic">
+                        No history recorded yet.
+                      </p>
+                    )}
+                  </TabsContent>
+                </div>
+              </Tabs>
             ) : (
               /* World/Experience view - with tabs */
               <Tabs

hindsight-control-plane/src/components/memory-detail-panel.tsx

@@ -3,7 +3,7 @@
 import { useState, useEffect } from "react";
 import { Button } from "@/components/ui/button";
 import { TagList } from "@/components/ui/tag-list";
-import { Copy, Check, X, Loader2, Calendar } from "lucide-react";
+import { Copy, Check, X, Loader2, Calendar, History } from "lucide-react";
 import { DocumentChunkModal } from "./document-chunk-modal";
 import { MemoryDetailModal } from "./memory-detail-modal";
 import { client } from "@/lib/api";
@@ -29,6 +29,7 @@ export function MemoryDetailPanel({
   const [fullMemory, setFullMemory] = useState<any>(null);
   const [loading, setLoading] = useState(false);
   const [sourceMemoryModalId, setSourceMemoryModalId] = useState<string | null>(null);
+  const [historyModalOpen, setHistoryModalOpen] = useState(false);
 
   // Fetch full memory data when panel opens
   // For mental models, use getMentalModel to get source memories
@@ -296,6 +297,20 @@ export function MemoryDetailPanel({
                 </div>
               )}
 
+              {/* View History button (observations only) */}
+              {isObservation && (
+                <div className="border-t border-border pt-5">
+                  <Button
+                    variant="outline"
+                    className="w-full flex items-center gap-2"
+                    onClick={() => setHistoryModalOpen(true)}
+                  >
+                    <History className="h-4 w-4" />
+                    View History
+                  </Button>
+                </div>
+              )}
+
               {/* Memory ID */}
               {memoryId && (
                 <div>
@@ -333,6 +348,15 @@ export function MemoryDetailPanel({
           memoryId={sourceMemoryModalId}
           onClose={() => setSourceMemoryModalId(null)}
         />
+
+        {/* History Modal */}
+        {historyModalOpen && memoryId && bankId && (
+          <MemoryDetailModal
+            memoryId={memoryId}
+            onClose={() => setHistoryModalOpen(false)}
+            initialTab="history"
+          />
+        )}
       </>
     );
   }

hindsight-control-plane/src/components/observation-history-view.tsx

@@ -0,0 +1,296 @@
+"use client";
+
+import { useState } from "react";
+import { ChevronLeft, ChevronRight } from "lucide-react";
+import { Button } from "@/components/ui/button";
+
+export interface HistoryEntry {
+  previous_text: string;
+  previous_tags: string[];
+  previous_occurred_start: string | null;
+  previous_occurred_end: string | null;
+  previous_mentioned_at: string | null;
+  changed_at: string;
+  new_source_memory_ids: string[];
+  source_facts?: {
+    id: string;
+    text: string | null;
+    type: string | null;
+    context: string | null;
+    is_new: boolean;
+  }[];
+}
+
+interface CurrentState {
+  text: string;
+  tags: string[];
+  occurred_start: string | null;
+  occurred_end: string | null;
+  mentioned_at: string | null;
+}
+
+function diffWords(a: string, b: string): { type: "same" | "removed" | "added"; text: string }[] {
+  const aWords = a.split(/(\s+)/);
+  const bWords = b.split(/(\s+)/);
+  const m = aWords.length;
+  const n = bWords.length;
+  const dp: number[][] = Array.from({ length: m + 1 }, () => new Array(n + 1).fill(0));
+  for (let i = 1; i <= m; i++) {
+    for (let j = 1; j <= n; j++) {
+      dp[i][j] =
+        aWords[i - 1] === bWords[j - 1]
+          ? dp[i - 1][j - 1] + 1
+          : Math.max(dp[i - 1][j], dp[i][j - 1]);
+    }
+  }
+  let i = m,
+    j = n;
+  const ops: { type: "same" | "removed" | "added"; text: string }[] = [];
+  while (i > 0 || j > 0) {
+    if (i > 0 && j > 0 && aWords[i - 1] === bWords[j - 1]) {
+      ops.push({ type: "same", text: aWords[i - 1] });
+      i--;
+      j--;
+    } else if (j > 0 && (i === 0 || dp[i][j - 1] >= dp[i - 1][j])) {
+      ops.push({ type: "added", text: bWords[j - 1] });
+      j--;
+    } else {
+      ops.push({ type: "removed", text: aWords[i - 1] });
+      i--;
+    }
+  }
+  return ops.reverse();
+}
+
+function TextDiff({ before, after }: { before: string; after: string }) {
+  const parts = diffWords(before, after);
+  const hasChanges = parts.some((p) => p.type !== "same");
+  if (!hasChanges) return <span className="text-sm text-muted-foreground italic">unchanged</span>;
+  return (
+    <span className="text-sm leading-relaxed">
+      {parts.map((part, idx) =>
+        part.type === "same" ? (
+          <span key={idx}>{part.text}</span>
+        ) : part.type === "removed" ? (
+          <span
+            key={idx}
+            className="bg-red-500/15 text-red-700 dark:text-red-400 line-through rounded-sm px-0.5"
+          >
+            {part.text}
+          </span>
+        ) : (
+          <span
+            key={idx}
+            className="bg-green-500/15 text-green-700 dark:text-green-400 rounded-sm px-0.5"
+          >
+            {part.text}
+          </span>
+        )
+      )}
+    </span>
+  );
+}
+
+function TagsDiff({ before, after }: { before: string[]; after: string[] }) {
+  const removed = before.filter((t) => !after.includes(t));
+  const added = after.filter((t) => !before.includes(t));
+  const kept = before.filter((t) => after.includes(t));
+  if (removed.length === 0 && added.length === 0)
+    return <span className="text-sm text-muted-foreground italic">unchanged</span>;
+  return (
+    <div className="flex gap-1 flex-wrap">
+      {kept.map((t, idx) => (
+        <span
+          key={idx}
+          className="text-[10px] px-1.5 py-0.5 rounded-md bg-amber-500/10 text-amber-700 border border-amber-500/20 font-mono"
+        >
+          #{t}
+        </span>
+      ))}
+      {removed.map((t, idx) => (
+        <span
+          key={idx}
+          className="text-[10px] px-1.5 py-0.5 rounded-md bg-red-500/15 text-red-700 dark:text-red-400 border border-red-500/20 font-mono line-through"
+        >
+          #{t}
+        </span>
+      ))}
+      {added.map((t, idx) => (
+        <span
+          key={idx}
+          className="text-[10px] px-1.5 py-0.5 rounded-md bg-green-500/15 text-green-700 dark:text-green-400 border border-green-500/20 font-mono"
+        >
+          +#{t}
+        </span>
+      ))}
+    </div>
+  );
+}
+
+function DateDiff({
+  label,
+  before,
+  after,
+}: {
+  label: string;
+  before: string | null;
+  after: string | null;
+}) {
+  if (!before && !after) return null;
+  const changed = before !== after;
+  return (
+    <div>
+      <span className="text-xs text-muted-foreground">{label}: </span>
+      {changed ? (
+        <>
+          <span className="text-xs bg-red-500/15 text-red-700 dark:text-red-400 line-through rounded-sm px-0.5">
+            {before ? new Date(before).toLocaleString() : "—"}
+          </span>
+          {" → "}
+          <span className="text-xs bg-green-500/15 text-green-700 dark:text-green-400 rounded-sm px-0.5">
+            {after ? new Date(after).toLocaleString() : "—"}
+          </span>
+        </>
+      ) : (
+        <span className="text-xs">{after ? new Date(after).toLocaleString() : "—"}</span>
+      )}
+    </div>
+  );
+}
+
+function SourceFactItem({ fact }: { fact: NonNullable<HistoryEntry["source_facts"]>[number] }) {
+  const typeColors =
+    fact.type === "experience"
+      ? "bg-green-500/10 text-green-700 dark:text-green-400"
+      : "bg-blue-500/10 text-blue-700 dark:text-blue-400";
+
+  return (
+    <div
+      className={`p-2 rounded border space-y-1 ${
+        fact.is_new ? "border-green-500/40 bg-green-500/5" : "border-border/50 bg-muted/30"
+      }`}
+    >
+      <div className="flex items-center gap-1.5">
+        {fact.type && (
+          <span
+            className={`text-[10px] px-1.5 py-0.5 rounded font-medium flex-shrink-0 ${typeColors}`}
+          >
+            {fact.type}
+          </span>
+        )}
+        {fact.is_new && (
+          <span className="text-[10px] px-1.5 py-0.5 rounded font-medium bg-green-500/15 text-green-700 dark:text-green-400 border border-green-500/30">
+            new
+          </span>
+        )}
+        {fact.context && (
+          <span className="text-[10px] text-muted-foreground italic truncate">{fact.context}</span>
+        )}
+      </div>
+      {fact.text ? (
+        <p className="text-xs text-foreground leading-relaxed">{fact.text}</p>
+      ) : (
+        <p className="text-xs text-muted-foreground italic">(memory no longer available)</p>
+      )}
+    </div>
+  );
+}
+
+export function ObservationHistoryView({
+  history,
+  current,
+}: {
+  history: HistoryEntry[];
+  current: CurrentState;
+}) {
+  // index 0 = most recent change
+  const entries = [...history].reverse();
+  const [idx, setIdx] = useState(0);
+
+  const entry = entries[idx];
+  const isLatest = idx === 0;
+  const afterText = isLatest ? current.text : entries[idx - 1].previous_text;
+  const afterTags = isLatest ? current.tags : entries[idx - 1].previous_tags;
+  const afterOccurredStart = isLatest
+    ? current.occurred_start
+    : entries[idx - 1].previous_occurred_start;
+  const afterOccurredEnd = isLatest ? current.occurred_end : entries[idx - 1].previous_occurred_end;
+  const afterMentionedAt = isLatest ? current.mentioned_at : entries[idx - 1].previous_mentioned_at;
+
+  return (
+    <div className="space-y-3">
+      {/* Navigation header */}
+      <div className="flex items-center justify-between">
+        <span className="text-xs text-muted-foreground">
+          Change <span className="font-semibold text-foreground">{history.length - idx}</span> of{" "}
+          {history.length} &middot; {new Date(entry.changed_at).toLocaleString()}
+        </span>
+        <div className="flex items-center gap-1">
+          <Button
+            variant="outline"
+            size="sm"
+            className="h-7 w-7 p-0"
+            disabled={idx === entries.length - 1}
+            onClick={() => setIdx(idx + 1)}
+          >
+            <ChevronLeft className="h-3.5 w-3.5" />
+          </Button>
+          <Button
+            variant="outline"
+            size="sm"
+            className="h-7 w-7 p-0"
+            disabled={idx === 0}
+            onClick={() => setIdx(idx - 1)}
+          >
+            <ChevronRight className="h-3.5 w-3.5" />
+          </Button>
+        </div>
+      </div>
+
+      {/* Change card */}
+      <div className="border border-border rounded-lg p-3 space-y-3">
+        <div>
+          <div className="text-xs font-bold text-muted-foreground uppercase mb-1">Text</div>
+          <TextDiff before={entry.previous_text} after={afterText} />
+        </div>
+
+        <div>
+          <div className="text-xs font-bold text-muted-foreground uppercase mb-1">Tags</div>
+          <TagsDiff before={entry.previous_tags} after={afterTags} />
+        </div>
+
+        <div className="space-y-1">
+          <div className="text-xs font-bold text-muted-foreground uppercase mb-1">Dates</div>
+          <DateDiff
+            label="Occurred start"
+            before={entry.previous_occurred_start}
+            after={afterOccurredStart}
+          />
+          <DateDiff
+            label="Occurred end"
+            before={entry.previous_occurred_end}
+            after={afterOccurredEnd}
+          />
+          <DateDiff
+            label="Mentioned at"
+            before={entry.previous_mentioned_at}
+            after={afterMentionedAt}
+          />
+        </div>
+
+        {entry.source_facts && entry.source_facts.length > 0 && (
+          <div>
+            <div className="text-xs font-bold text-muted-foreground uppercase mb-2">
+              Source Facts ({entry.source_facts.length})
+            </div>
+            <div className="space-y-1.5">
+              {entry.source_facts.map((fact) => (
+                <SourceFactItem key={fact.id} fact={fact} />
+              ))}
+            </div>
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}

hindsight-control-plane/src/lib/api.ts

@@ -413,9 +413,42 @@ export class ControlPlaneClient {
       chunk_id: string | null;
       tags: string[];
       observation_scopes: string | string[][] | null;
+      history?: {
+        previous_text: string;
+        previous_tags: string[];
+        previous_occurred_start: string | null;
+        previous_occurred_end: string | null;
+        previous_mentioned_at: string | null;
+        changed_at: string;
+        new_source_memory_ids: string[];
+      }[];
     }>(`/api/memories/${memoryId}?bank_id=${bankId}`);
   }
 
+  /**
+   * Get the history of an observation with resolved source facts
+   */
+  async getObservationHistory(memoryId: string, bankId: string) {
+    return this.fetchApi<
+      {
+        previous_text: string;
+        previous_tags: string[];
+        previous_occurred_start: string | null;
+        previous_occurred_end: string | null;
+        previous_mentioned_at: string | null;
+        changed_at: string;
+        new_source_memory_ids: string[];
+        source_facts: {
+          id: string;
+          text: string | null;
+          type: string | null;
+          context: string | null;
+          is_new: boolean;
+        }[];
+      }[]
+    >(`/api/memories/${memoryId}/history?bank_id=${bankId}`);
+  }
+
   /**
    * Get bank profile
    */

hindsight-control-plane/tsconfig.json

@@ -34,7 +34,23 @@
     "**/*.tsx",
     ".next/types/**/*.ts",
     ".next/dev/types/**/*.ts",
-    "types/**/*.d.ts"
+    "types/**/*.d.ts",
+    ".next-*/types/**/*.ts",
+    ".next-*/dev/types/**/*.ts",
+    ".next-49944/types/**/*.ts",
+    ".next-49944/dev/types/**/*.ts",
+    ".next-50612/types/**/*.ts",
+    ".next-50612/dev/types/**/*.ts",
+    ".next-54508/types/**/*.ts",
+    ".next-54508/dev/types/**/*.ts",
+    ".next-55630/types/**/*.ts",
+    ".next-55630/dev/types/**/*.ts",
+    ".next-58976/types/**/*.ts",
+    ".next-58976/dev/types/**/*.ts",
+    ".next-64080/types/**/*.ts",
+    ".next-64080/dev/types/**/*.ts",
+    ".next-50432/types/**/*.ts",
+    ".next-50432/dev/types/**/*.ts"
   ],
   "exclude": [
     "node_modules"

hindsight-docs/static/openapi.json

@@ -322,7 +322,7 @@
           "Memory"
         ],
         "summary": "Get memory unit",
-        "description": "Get a single memory unit by ID with all its metadata including entities and tags.",
+        "description": "Get a single memory unit by ID with all its metadata including entities and tags. Note: the 'history' field is deprecated and always returns an empty list - use GET /memories/{memory_id}/history instead.",
         "operationId": "get_memory",
         "parameters": [
           {
@@ -382,6 +382,72 @@
         }
       }
     },
+    "/v1/default/banks/{bank_id}/memories/{memory_id}/history": {
+      "get": {
+        "tags": [
+          "Memory"
+        ],
+        "summary": "Get observation history",
+        "description": "Get the full history of an observation, with each change's source facts resolved to their text.",
+        "operationId": "get_observation_history",
+        "parameters": [
+          {
+            "name": "bank_id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "title": "Bank Id"
+            }
+          },
+          {
+            "name": "memory_id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "title": "Memory Id"
+            }
+          },
+          {
+            "name": "authorization",
+            "in": "header",
+            "required": false,
+            "schema": {
+              "anyOf": [
+                {
+                  "type": "string"
+                },
+                {
+                  "type": "null"
+                }
+              ],
+              "title": "Authorization"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Successful Response",
+            "content": {
+              "application/json": {
+                "schema": {}
+              }
+            }
+          },
+          "422": {
+            "description": "Validation Error",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HTTPValidationError"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/v1/default/banks/{bank_id}/memories/recall": {
       "post": {
         "tags": [

scripts/dev/start-control-plane.sh

@@ -18,6 +18,10 @@ echo "✅ SDK built successfully"
 echo ""
 
 echo "🚀 Starting Control Plane (Next.js dev server)..."
+# Save caller-provided values before .env can overwrite them
+_CALLER_PORT="${PORT:-}"
+_CALLER_DATAPLANE_URL="${HINDSIGHT_CP_DATAPLANE_API_URL:-}"
+
 if [ -f "$ROOT_DIR/.env" ]; then
   echo "📄 Loading environment from $ROOT_DIR/.env"
   # Load env vars from root .env file
@@ -28,7 +32,9 @@ fi
 
 # Map prefixed env vars to Next.js standard vars
 export HOSTNAME="${HINDSIGHT_CP_HOSTNAME:-0.0.0.0}"
-export PORT="${HINDSIGHT_CP_PORT:-9999}"
+# Caller-provided values take priority over .env
+export PORT="${_CALLER_PORT:-${HINDSIGHT_CP_PORT:-9999}}"
+export HINDSIGHT_CP_DATAPLANE_API_URL="${_CALLER_DATAPLANE_URL:-${HINDSIGHT_CP_DATAPLANE_API_URL:-http://localhost:8888}}"
 
 # Run dev server
 npm run dev -w @vectorize-io/hindsight-control-plane

scripts/dev/start.sh

@@ -3,6 +3,14 @@ set -e
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 
+# Parse --random-port flag
+RANDOM_PORT=false
+for arg in "$@"; do
+    if [ "$arg" = "--random-port" ]; then
+        RANDOM_PORT=true
+    fi
+done
+
 # Load .env to pick up HINDSIGHT_API_PORT if set
 ROOT_DIR="$(git rev-parse --show-toplevel)"
 if [ -f "$ROOT_DIR/.env" ]; then
@@ -10,8 +18,19 @@ if [ -f "$ROOT_DIR/.env" ]; then
     source "$ROOT_DIR/.env"
     set +a
 fi
+
+get_free_port() {
+    python3 -c "import socket; s=socket.socket(); s.bind(('', 0)); print(s.getsockname()[1]); s.close()"
+}
+
+if [ "$RANDOM_PORT" = true ]; then
+    API_PORT="$(get_free_port)"
+    CP_PORT="$(get_free_port)"
+    echo "Using random ports — API: $API_PORT, Control Plane: $CP_PORT"
+else
     API_PORT="${HINDSIGHT_API_PORT:-8888}"
     CP_PORT="${HINDSIGHT_CP_PORT:-9999}"
+fi
 
 PIDS=()
 
@@ -37,7 +56,7 @@ trap cleanup EXIT INT TERM
 
 # Start API
 echo "Starting API server..."
-"$SCRIPT_DIR/start-api.sh" &
+"$SCRIPT_DIR/start-api.sh" --port "$API_PORT" &
 API_PID=$!
 PIDS+=($API_PID)
 
@@ -63,7 +82,7 @@ fi
 
 # Start Control Plane
 echo ""
-"$SCRIPT_DIR/start-control-plane.sh" &
+PORT="$CP_PORT" HINDSIGHT_CP_DATAPLANE_API_URL="http://localhost:${API_PORT}" "$SCRIPT_DIR/start-control-plane.sh" &
 CP_PID=$!
 PIDS+=($CP_PID)