feat(intake): reduce data loaded for nemo studio trace views

services/intake/src/nmp/intake/api/v2/experiments/endpoints.py

@@ -25,6 +25,7 @@
 from nmp.common.entities.client import EntityClient, EntityConflictError, EntityNotFoundError
 from nmp.common.service.dependencies import get_entity_client
 from nmp.intake.api.v2.experiments.schemas import (
+    EXPERIMENT_SESSION_SUMMARY_INPUT_CHAR_LIMIT,
     EvaluatorAggregate,
     ExperimentFilter,
     ExperimentGroupFilter,
@@ -33,6 +34,7 @@
     ExperimentRequest,
     ExperimentResponse,
     ExperimentSessionFilter,
+    ExperimentSessionMode,
     ExperimentSessionResponse,
 )
 from nmp.intake.entities.experiments import Experiment, ExperimentGroup, SortCriterion
@@ -654,6 +656,13 @@ async def list_experiment_sessions(
     parsed: ExperimentSessionFilterDep,
     page: int = Query(default=1, ge=1, description="Page number."),
     page_size: int = Query(default=100, ge=1, le=1000, description="Page size."),
+    mode: ExperimentSessionMode = Query(
+        default="detailed",
+        description=(
+            "Response payload mode. summary keeps the same session row fields but truncates root-span input "
+            "to 1000 characters; detailed returns the full root-span input."
+        ),
+    ),
 ) -> Page[ExperimentSessionResponse]:
     validate_list_query_params(request)
     experiment = await _get_or_404(
@@ -686,6 +695,7 @@ async def list_experiment_sessions(
             test_case_id=test_case_id,
             page=page,
             page_size=page_size,
+            input_char_limit=EXPERIMENT_SESSION_SUMMARY_INPUT_CHAR_LIMIT if mode == "summary" else None,
         )
     except Exception as exc:
         # Sessions are the response payload (not enrichment), so we can't silently degrade like

services/intake/src/nmp/intake/api/v2/experiments/schemas.py

@@ -10,14 +10,17 @@
 from __future__ import annotations
 
 from datetime import datetime
-from typing import Annotated, Any
+from typing import Annotated, Any, Literal
 
 from nmp.common.entities.values import DatetimeFilter, Filter, NumberFilter, map_entity_field
 from nmp.intake.entities.experiments import Experiment, ExperimentGroup, SortCriterion
 from nmp.intake.spans.domain import SpanStatus
 from nmp.intake.spans.experiment_session_repository import ExperimentSessionRow
 from pydantic import AnyUrl, BaseModel, ConfigDict, Field
 
+ExperimentSessionMode = Literal["summary", "detailed"]
+EXPERIMENT_SESSION_SUMMARY_INPUT_CHAR_LIMIT = 1000
+
 
 class ExperimentGroupRequest(BaseModel):
     """Request body for creating an ExperimentGroup."""
@@ -292,7 +295,13 @@ class ExperimentSessionResponse(BaseModel):
     latency_ms: float | None = None
 
     status: SpanStatus = Field(description="Root-span status: success, error, cancelled, or unknown.")
-    input: str | None = Field(default=None, description="Root-span input text (the query).")
+    input: str | None = Field(
+        default=None,
+        description=(
+            "Root-span input text. In summary mode this is truncated to "
+            f"{EXPERIMENT_SESSION_SUMMARY_INPUT_CHAR_LIMIT} characters."
+        ),
+    )
 
     input_tokens: int | None = Field(default=None, description="Sum of input tokens across this session's spans.")
     output_tokens: int | None = Field(default=None, description="Sum of output tokens across this session's spans.")

services/intake/src/nmp/intake/spans/api/spans_schemas.py

@@ -35,6 +35,7 @@ class SpanGroupBy(StrEnum):
 
 
 SpanMode = Literal["summary", "detailed"]
+SPAN_SUMMARY_ERROR_MESSAGE_CHAR_LIMIT = 1000
 
 
 class SpanFilter(BaseModel):
@@ -130,7 +131,13 @@ class Span(BaseModel):
     ended_at: datetime | None = None
     status: SpanStatus
     error_type: str | None = None
-    error_message: str | None = None
+    error_message: str | None = Field(
+        default=None,
+        description=(
+            "Normalized error message. In summary mode this is truncated to "
+            f"{SPAN_SUMMARY_ERROR_MESSAGE_CHAR_LIMIT} characters."
+        ),
+    )
     provider: str | None = None
     model: str | None = None
     prompt_id: str | None = None
@@ -176,7 +183,7 @@ def from_domain(cls, span: IntakeSpan, *, mode: SpanMode = "detailed") -> Self:
             ended_at=span.end_time,
             status=span.status,
             error_type=semantic_attributes.error_type,
-            error_message=None if summary else semantic_attributes.error_message,
+            error_message=_error_message_for_mode(semantic_attributes.error_message, summary=summary),
             provider=semantic_attributes.provider,
             model=semantic_attributes.model,
             prompt_id=semantic_attributes.prompt_id,
@@ -241,3 +248,9 @@ def _float_or_none(value: object) -> float | None:
     if isinstance(value, str | int | float | Decimal):
         return float(value)
     raise TypeError(f"Expected float-compatible span value, got {type(value).__name__}")
+
+
+def _error_message_for_mode(value: str | None, *, summary: bool) -> str | None:
+    if value is None or not summary:
+        return value
+    return value[:SPAN_SUMMARY_ERROR_MESSAGE_CHAR_LIMIT]