[NOTICKET] fix(planner): a failed plan is not a data gap (P0-9)

TaskList._exhausted (private attr, not in the model's schema) marks a plan
that failed validation on every attempt; the coordinator shows its own text
without the data-gap lead. New EN/ID texts (register "Anda"): the plan failed
its checks, which does not mean the data is missing; ask more specifically.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/agents/planner/schemas.py

@@ -13,7 +13,7 @@ from __future__ import annotations
 import re
 from typing import Any, Literal
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, PrivateAttr
 
 from ..scope.models import ScopeChange
 
@@ -55,6 +55,11 @@ class Task(BaseModel):
 
 
 class TaskList(BaseModel):
+    # Set by PlannerService when every attempt failed validation (audit P0-9): the
+    # answer then says the PLAN failed, not that the data lacks the measure. Private,
+    # so it is not in the structured-output schema the model fills.
+    _exhausted: bool = PrivateAttr(default=False)
+
     plan_id: str
     goal_restated: str
     assumptions: list[str] = Field(default_factory=list)

src/agents/planner/service.py

@@ -263,12 +263,14 @@ class PlannerService:
             attempts=self._max_retries,
             errors=previous_errors,
         )
-        return TaskList(
+        exhausted = TaskList(
             plan_id=context.project_id,
             goal_restated=query,
             tasks=[],
             infeasible_reason=_exhausted_reason(reply_language),
         )
+        exhausted._exhausted = True
+        return exhausted
 
 
 async def plan_analysis(
@@ -306,17 +308,21 @@ def _schema_error(exc: Exception) -> str:
 #: What the user sees when the planner could not build a valid plan. Deliberately
 #: says what happened in THEIR terms and does not quote the validator: they cannot
 #: act on "not a declared foreign key", and it is not their problem.
+# Audit P0-9 (2026-11-03): these used to blame the data ("the measure may not be in
+# the catalog") and were shown under the data-gap lead, so a chart request right after
+# the user SAW the data read as "the data cannot answer" twice. Exhaustion means the
+# plan failed its own checks — say that. Indonesian register: "Anda" (decision D2).
 _EXHAUSTED_EN = (
-    "I could not work out a way to answer that from the data connected to this "
-    "analysis. It may need a measure that is not in the catalog, or a link between "
-    "tables that this source does not define. Try asking about one table at a time, "
-    "or name the exact columns you mean."
+    "I couldn't put together a working analysis for that question — my plan kept "
+    "failing its own checks. That does not mean the data is missing. Please ask again "
+    "more specifically (name the measure, the period and the unit or site), or split "
+    "it into two questions."
 )
 _EXHAUSTED_ID = (
-    "Saya belum menemukan cara menjawab pertanyaan itu dari data yang terhubung ke "
-    "analisis ini. Kemungkinan ukurannya tidak ada di katalog, atau butuh kaitan "
-    "antar tabel yang tidak didefinisikan di sumber ini. Coba tanyakan satu tabel "
-    "saja, atau sebutkan kolom yang kamu maksud."
+    "Saya belum berhasil menyusun analisis untuk pertanyaan itu — setelah beberapa kali "
+    "mencoba, rencana analisisnya masih gagal pemeriksaan internal. Ini tidak berarti "
+    "datanya tidak ada. Silakan ajukan lagi dengan lebih spesifik (sebutkan ukuran, "
+    "periode, dan unit atau site-nya), atau pecah menjadi dua pertanyaan."
 )