diff --git a/docs/investigation-contract-v2.md b/docs/investigation-contract-v2.md
index 1e514e5..18d7c8f 100644
--- a/docs/investigation-contract-v2.md
+++ b/docs/investigation-contract-v2.md
@@ -60,3 +60,49 @@ Cache-Aufteilung und frühe Diagnose-Routingentscheidung.
 
 Validierung am 20.10.2026: 307 lokale Tests bestanden (171,87 Sekunden),
 `git diff --check` ohne Befund. Keine kostenpflichtigen LLM-Tests ausgeführt.
+
+
+## Quellenraum und gezielte Korrekturen (20.10.2026)
+
+Neue v2-Kontexte speichern `research_guidance_version=1`. Ein kleiner, im stabilen
+Fallkontext cachebarer Quellenkatalog unterscheidet konfigurierte Git-Recherche
+(`project.query`) von den deklarierten Dateien im Paket (`source.*`). Höchstens
+drei Paketpfade mit zusammen höchstens 700 Zeichen werden aufgeführt; weitere
+Referenzen werden als ausgelassen gezählt. Historische Kontexte und ihre Requests
+bleiben unverändert rekonstruierbar. Die vollständige Eingabe unterliegt weiterhin
+der bestehenden 20.000-Zeichen-Grenze und dem 10.000-Zeichen-Richtwert.
+
+Fehlender Query-Kind, unvollständige `source.search`-Argumente und falscher
+Quellenraum erhalten kurze, feldbezogene Hinweise. Es werden weder fehlende
+Argumente erfunden noch Repository-Pfade automatisch in Paketquellen umgedeutet.
+Die Hinweise passen in das bestehende Limit von 160 Zeichen.
+
+Die Antwortreparatur entfernt bei einem bekannten, einzelnen `recall` lediglich
+die eindeutige `arguments`-Hülle. Beleg-ID, optionale Seitennummer, Beobachtung und
+Bewertung bleiben erhalten. Mehrdeutige Hüllen, unbekannte IDs, mehrere Belege,
+negative oder nicht ganzzahlige Seiten und unbekannte Aktionen werden nicht
+repariert. Anschließend gelten unverändert Schema-, Provenienz-, Seiten- und
+Budgetprüfungen; Originalantwort und Reparaturregel werden protokolliert.
+
+Die neue allgemeine Untersuchungsanweisung verlangt bei vermeintlich fehlenden
+Hooks auch Aufrufer, Overrides, indirekte Übergaben und Registrierung zu prüfen.
+Vorhandener Implementierungscode allein ist kein Beleg für einen Defekt. Das
+ändert keine gespeicherten Confidence-Werte und erzwingt keine Bug17-spezifische
+Schlussfolgerung. Ob diese Anleitung die fachliche Qualität verbessert, muss ein
+späterer LLM-Lauf zeigen.
+
+
+Der blockierte Bug17-Lauf wurde ohne API-Aufruf von Generation 204 über einen
+protokollierten manuellen technischen Retry auf Generation 206 vorbereitet.
+806 vorhandene Archiveinträge bleiben erhalten; Budget, Hypothesenstände und
+Versuchsnummer bleiben unverändert. Der neue Kontext ergänzt ausschließlich die
+versionierten Quellenhinweise und den fehlenden Korrekturhinweis. Die vollständige
+logische Anfrage misst 13.849 Zeichen einschließlich Cache-Kontext. Der portable
+Paketvalidator akzeptiert die Ausgabe. Details:
+`test-results/token-usage/bug17-source-contract-repair-20261020.json`.
+
+Validierung der Quellenkorrekturen: 269 lokale Regressionstests bestanden in
+192,85 Sekunden. Darunter 18 gezielte Tests für die kuratierten Suchfehler,
+eindeutige und verweigerte Recall-Reparaturen, vollständige Controller-Prüfung,
+Budgetneutralität, Cache-Aufteilung und die Zeichenobergrenze.
+`git diff --check` ohne Befund; keine kostenpflichtigen Aufrufe.
diff --git a/docs/test-results/token-usage/bug17-source-contract-repair-20261020.json b/docs/test-results/token-usage/bug17-source-contract-repair-20261020.json
new file mode 100644
index 0000000..770671e
--- /dev/null
+++ b/docs/test-results/token-usage/bug17-source-contract-repair-20261020.json
@@ -0,0 +1,20 @@
+{
+  "date": "2026-10-20",
+  "case_id": "BUG-000017",
+  "package_id": "trial-bounded-full-BUG-000017-20261020",
+  "from_generation": 204,
+  "to_generation": 206,
+  "state": "INVESTIGATING_HYPOTHESES",
+  "api_calls": 0,
+  "full_logical_input_characters": 13849,
+  "preserved_original_entries": 806,
+  "budget_unchanged": true,
+  "hypothesis_states_unchanged": true,
+  "active_attempt_unchanged": true,
+  "new_context_ref": "analysis/investigation/0001/contexts/H1-0019-attempt-0003-guidance-v1.json",
+  "changes": [
+    "manual technical retry",
+    "append versioned source guidance and precise rejection details"
+  ],
+  "package_valid": true
+}
diff --git a/src/viano_bug_analysis/analysis/investigation_contract.py b/src/viano_bug_analysis/analysis/investigation_contract.py
index 2b4cfb4..c7a096b 100644
--- a/src/viano_bug_analysis/analysis/investigation_contract.py
+++ b/src/viano_bug_analysis/analysis/investigation_contract.py
@@ -127,6 +127,17 @@ def feedback(error, document):
           and action.get('operation') == 'project.query' and 'arguments' not in action):
         result.update(validation_path='/next/arguments', validation_fields=['arguments'],
                       requirement='next.arguments must contain one complete query object, including its query kind; do not flatten query fields into next or infer missing values')
+    elif (path.startswith('/next') and isinstance(action,dict) and action.get('kind') == 'tool'
+            and action.get('operation') == 'project.query' and isinstance(action.get('arguments'),dict)
+            and 'kind' not in action['arguments']):
+        result.update(validation_path='/next/arguments/kind',validation_fields=['kind'],
+            requirement='next.arguments.kind is required. Choose a literal query kind; source.search needs text,path_prefix,case_sensitive,offset,limit. Do not guess kind.')
+    elif (path.startswith('/next') and isinstance(action,dict) and action.get('operation') == 'project.query'
+            and isinstance(action.get('arguments'),dict) and action['arguments'].get('kind') == 'source.search'):
+        result['requirement'] = 'source.search requires kind,text,path_prefix,case_sensitive,offset,limit. Supply missing fields; offset >= 0, limit > 0 within configured maximum. Keep intent.'
+    elif path.startswith('/next') and isinstance(action,dict) and action.get('kind') == 'recall' and 'arguments' in action:
+        result.update(validation_path='/next',validation_fields=['evidence_refs','page'],
+            requirement='recall has evidence_refs and optional page directly in next, without arguments; preserve the requested evidence ID and page')
     elif '/entity_refs' in path:
         result['requirement'] = 'entity_refs must use exact N references from input.entities; raw domain IDs are not references; never invent or guess a mapping'
     elif path == '/next/arguments' and isinstance(action,dict) and isinstance(action.get('arguments'),dict) and 'choices' in action['arguments']:
diff --git a/src/viano_bug_analysis/analysis/investigation_window.py b/src/viano_bug_analysis/analysis/investigation_window.py
index 6409461..7ef9ea7 100644
--- a/src/viano_bug_analysis/analysis/investigation_window.py
+++ b/src/viano_bug_analysis/analysis/investigation_window.py
@@ -232,6 +232,9 @@ def project(request, context):
     if v2(context):
         from .investigation_contract import entity_catalog
         view['entities'] = entity_catalog(context)
+    if context.get('research_guidance_version') == 1:
+        from .research_guidance import source_access
+        view['source_access'] = source_access(context)
     evidence = context['evidence']
     ordered = sorted(evidence)
     previous = context.get('previous_result')
@@ -251,6 +254,9 @@ def project(request, context):
         if key in old: body[key] = old[key]
     result['messages'] = [{'role': 'system', 'content': instructions_v2() if v2(context) else INSTRUCTIONS},
                           {'role': 'user', 'content': compact(body)}]
+    if context.get('research_guidance_version') == 1:
+        from .research_guidance import INSTRUCTIONS as research_instructions
+        result['messages'][0]['content'] += research_instructions
     if context.get('startup_explore'):
         result['messages'][0]['content'] += '\nInitial round: assessment=null; choose a tool only. No consolidation or confidence update.'
     def refresh():
diff --git a/src/viano_bug_analysis/analysis/investigator.py b/src/viano_bug_analysis/analysis/investigator.py
index 0aa94a4..4e2f1ba 100644
--- a/src/viano_bug_analysis/analysis/investigator.py
+++ b/src/viano_bug_analysis/analysis/investigator.py
@@ -249,6 +249,7 @@ class Investigator:
         if state['policy'].get('prompt_window_version') == 2:
             # Frozen per context: historical requests remain reconstructable.
             context['assessment_scope_version'] = 1
+            context['research_guidance_version'] = 1
         if state.get("prompt_protocol") == 2:
             context["prompt_version"] = "investigation_project_v2"
             context["case_sources"] = interpretation_context["sources"]
@@ -490,8 +491,12 @@ class Investigator:
         except (InvestigationError,CaseBuildError,BudgetError,ToolError) as error:
             if getattr(error,"code",None) in {"PROJECT_PROVIDER_UNAVAILABLE", "PROJECT_SOURCE_UNAVAILABLE", "PROJECT_DATABASE_UNAVAILABLE", "PROJECT_DATABASE_CREDENTIALS", "PROJECT_DATABASE_DRIVER", "PROJECT_BINDING_CHANGED"}:
                 return self._research_blocked(state,error.code)
+            detail = getattr(error,'feedback',None)
+            if getattr(error,'code',None) == 'TOOL_SOURCE_NOT_DECLARED' and context['policy'].get('prompt_window_version') == 2:
+                from .research_guidance import namespace_feedback
+                detail = namespace_feedback(decision.get('next')) or detail
             return self._invalid(state,budget,getattr(error,"code","INVESTIGATION_OUTPUT"),outcome.result_ref,
-                                 feedback=getattr(error,'feedback',None))
+                                 feedback=detail)
         active["decision"]=decision;active["llm_ref"]=outcome.result_ref;active["phase"]="executing"
         if call['outcome'].get('normalization'):
             state['pending_format_notice']=call['outcome']['normalization']['rules'][:16]
diff --git a/src/viano_bug_analysis/analysis/research_guidance.py b/src/viano_bug_analysis/analysis/research_guidance.py
new file mode 100644
index 0000000..385ea06
--- /dev/null
+++ b/src/viano_bug_analysis/analysis/research_guidance.py
@@ -0,0 +1,31 @@
+"""Small, versioned source namespaces and causal-method guidance; no bug rules."""
+
+
+def source_access(context):
+    refs = context.get('case',{}).get('source_context',{}).get('refs',[])
+    paths = [v['path'] for v in refs if isinstance(v,dict) and isinstance(v.get('path'),str)]
+    shown = []
+    for path in paths:
+        if len(shown) == 3 or sum(map(len,shown)) + len(path) > 700:
+            break
+        shown.append(path)
+    binding = context['tool_schema'].get('x-project-bindings',{})
+    return {'repository_available':bool(binding.get('source')),
+        'repository_operation':'project.query',
+        'repository_search_fields':['kind','text','path_prefix','case_sensitive','offset','limit'],
+        'package_operations':['source.find_text','source.find_symbol','source.read_context'],
+        'package_source_refs':shown,'omitted_package_source_refs':len(paths)-len(shown)}
+
+
+INSTRUCTIONS = '''
+Source namespaces: configured Git uses operation project.query and a complete query object. source.search requires kind,text,path_prefix,case_sensitive,offset,limit. Package source.* operations accept only exact package_source_refs, never repository paths. Do not guess missing kind or translate namespaces silently. Prefer source.context for call/binding analysis when available, then targeted primitives.
+Test the proposed mechanism, not just a preferred method name. Before declaring a hook missing, check callers, overrides, indirect delegation and registration. An absent wrapper method alone does not exclude another valid entry point. Existing implementation is neutral unless it establishes a causal defect; retrieve relevant contrary evidence. Distinguish not-yet-read from absent.'''
+
+
+def namespace_feedback(action):
+    if (not isinstance(action,dict) or action.get('kind') != 'tool'
+            or action.get('operation') not in {'source.find_text','source.find_symbol','source.read_context'}):
+        return None
+    field = 'source_ref' if action['operation'] == 'source.read_context' else 'source_refs'
+    return {'validation_path':'/next/arguments/'+field,'validation_fields':[field],
+        'requirement':'package source.* requires declared package_source_refs, not repository paths. For Git use project.query and a complete source.search query; Do not guess.'}
diff --git a/src/viano_bug_analysis/llm/response_recovery.py b/src/viano_bug_analysis/llm/response_recovery.py
index 7b031ea..7ded9b2 100644
--- a/src/viano_bug_analysis/llm/response_recovery.py
+++ b/src/viano_bug_analysis/llm/response_recovery.py
@@ -103,6 +103,28 @@ def normalize(document, *, request=None):
                 and isinstance(filters[1],str) and filters[1] in {'eq','ne','lt','le','gt','ge','contains','in'}):
             args['filters']=[dict(zip(('column','operator','value'),filters))]
             rules.append('flat_filter:/next/arguments/filters')
+    # A known recall has a single unambiguous container error. Never change its
+    # evidence ID/page, select a reference, invent a page or move sibling fields.
+    if (request and enabled(request) and request.get('output_schema',{}).get('x-viano-investigation-window') == 2
+            and isinstance(action,dict) and set(action) == {'kind','arguments'} and action['kind'] == 'recall'
+            and isinstance(args,dict) and set(args) in ({'evidence_refs'},{'evidence_refs','page'})
+            and isinstance(args.get('evidence_refs'),list) and len(args['evidence_refs']) == 1
+            and isinstance(args['evidence_refs'][0],str) and re.fullmatch(r'E[0-9]{6,}',args['evidence_refs'][0])
+            and ('page' not in args or type(args['page']) is int and args['page'] >= 0)):
+        try:
+            body = json.loads(request['messages'][1]['content'])
+            visible = set(body['input'].get('evidence',{})) | set(body['input'].get('archive',{}).get('recent_ids',[]))
+        except (ValueError,KeyError,IndexError,TypeError):
+            visible = set()
+        if args['evidence_refs'][0] in visible:
+            from jsonschema import Draft202012Validator
+            candidate = copy.deepcopy(result)
+            candidate['next'] = {'kind':'recall',**copy.deepcopy(args)}
+            if Draft202012Validator(request['output_schema']).is_valid(candidate):
+                result = candidate
+                action = result['next']
+                args = {}
+                rules.append('unwrap_recall_arguments:/next')
     # A recall is not a newly charged research action. Discard only a well-formed
     # but non-applicable budget score, never causal findings, evidence references,
     # action intent or missing required values. The original score stays audited.
diff --git a/src/viano_bug_analysis/llm/stable_context.py b/src/viano_bug_analysis/llm/stable_context.py
index a29732c..ebe99f9 100644
--- a/src/viano_bug_analysis/llm/stable_context.py
+++ b/src/viano_bug_analysis/llm/stable_context.py
@@ -62,7 +62,7 @@ def split_document(document, prompt_version):
         # Cache its one tool/response contract plus immutable, targeted case data.
         current = copy.deepcopy(document)
         stable_input = {k:current['input'].pop(k) for k in
-                        ('case','behavior','tool_profiles','entities') if k in current['input']}
+                        ('case','behavior','tool_profiles','entities','source_access') if k in current['input']}
         descriptor = {'encoding':'bounded_investigation_v1','input':stable_input,
                       'response_contract':current.pop('response_contract')}
         descriptor['id'] = hashlib.sha256(json_bytes(descriptor)).hexdigest()
diff --git a/src/viano_bug_analysis/schemas/investigation-context-v1.schema.json b/src/viano_bug_analysis/schemas/investigation-context-v1.schema.json
index b2c8b83..16742c7 100644
--- a/src/viano_bug_analysis/schemas/investigation-context-v1.schema.json
+++ b/src/viano_bug_analysis/schemas/investigation-context-v1.schema.json
@@ -904,6 +904,9 @@
     },
     "assessment_scope_version": {
       "const": 1
+    },
+    "research_guidance_version": {
+      "const": 1
     }
   }
 }
diff --git a/tests/test_source_search_recovery.py b/tests/test_source_search_recovery.py
new file mode 100644
index 0000000..a8c7beb
--- /dev/null
+++ b/tests/test_source_search_recovery.py
@@ -0,0 +1,156 @@
+import copy
+import json
+from pathlib import Path
+
+import pytest
+from jsonschema import Draft202012Validator
+
+from test_bounded_contract_v2 import context, loop_for
+from test_case_builder import case_setup
+from test_investigation_tools import tool_case
+from test_investigation_startup import Adapter
+from test_investigator import CASE, run, state
+from viano_bug_analysis.analysis.investigation_prompt import build_prompt
+from viano_bug_analysis.analysis.investigation_contract import feedback
+from viano_bug_analysis.analysis.research_guidance import source_access, namespace_feedback
+from viano_bug_analysis.llm.response_recovery import normalize
+from viano_bug_analysis.llm.stable_context import split_document, restore_document
+from viano_bug_analysis.llm.gemini import GeminiProvider
+from viano_bug_analysis.llm.investigation_size import check_wire
+from viano_bug_analysis.llm import ProviderResponse
+from viano_bug_analysis.package import PackageReader, PackageValidator
+from viano_bug_analysis.budget import BudgetManager
+from viano_bug_analysis.tools.project_query import ProjectResearch
+
+CORPUS = Path(__file__).parent/'fixtures/llm_rejections/20261020/bug17-source-search-contract'
+
+
+def captured(name):
+    folder = CORPUS/name
+    return tuple(json.loads((folder/f).read_text(encoding='utf-8')) for f in ['request.json','parsed-answer.json'])
+
+
+def test_nested_recall_is_recovered_without_changing_reference_page_or_assessment():
+    request,answer = captured('nested-recall')
+    before = copy.deepcopy(answer)
+    result,audit = normalize(answer,request=request)
+    assert result['next'] == {'kind':'recall',**answer['next']['arguments']}
+    assert result['assessment'] == answer['assessment']
+    assert result['observation'] == answer['observation'] and answer == before
+    assert audit['original_document'] == before
+    assert audit['rules'] == ['unwrap_recall_arguments:/next']
+    assert normalize(result,request=request) == (result,None)
+
+
+@pytest.mark.parametrize('change',['extra','sibling','many','unknown','negative','boolean','string','operation','legacy','disabled'])
+def test_ambiguous_recall_is_not_repaired(change):
+    request,answer = captured('nested-recall')
+    if change == 'extra': answer['next']['arguments']['other'] = 1
+    if change == 'sibling': answer['next']['page'] = 4
+    if change == 'many': answer['next']['arguments']['evidence_refs'].append('E000001')
+    if change == 'unknown': answer['next']['arguments']['evidence_refs'] = ['E999999']
+    if change == 'negative': answer['next']['arguments']['page'] = -1
+    if change == 'boolean': answer['next']['arguments']['page'] = True
+    if change == 'string': answer['next']['arguments']['page'] = '1'
+    if change == 'operation': answer['next']['operation'] = 'invented'
+    if change == 'legacy': request['output_schema']['x-viano-investigation-window'] = 1
+    if change == 'disabled': request['output_schema'].pop('x-viano-response-recovery')
+    assert normalize(answer,request=request) == (answer,None)
+
+
+@pytest.mark.parametrize('name,fields',[('eb01f48a',{'offset','limit'}),('a99adf87',{'kind'})])
+def test_actual_search_errors_get_precise_feedback_without_guessing(name,fields):
+    request,answer = captured(name)
+    query_schema = ProjectResearch.schema()
+    schema = {'properties':{'next':{'properties':{'arguments':query_schema}}}}
+    error = next(Draft202012Validator(schema).iter_errors(answer))
+    detail = feedback(error,answer)
+    assert fields <= set(detail['validation_fields'])
+    assert 'source.search' in detail['requirement']
+    assert len(detail['requirement']) <= 160
+    assert normalize(answer,request=request) == (answer,None)
+
+
+def test_package_reference_feedback_does_not_rewrite_or_echo_path():
+    request,answer = captured('60d98274')
+    detail = namespace_feedback(answer['next'])
+    assert detail['validation_path'] == '/next/arguments/source_refs'
+    assert 'project.query' in detail['requirement'] and 'package' in detail['requirement']
+    assert 'arathi' not in json.dumps(detail)
+    assert len(detail['requirement']) <= 160
+    assert normalize(answer,request=request) == (answer,None)
+
+
+def test_versioned_guidance_is_cached_bounded_and_generic():
+    c = context();old = build_prompt(c)
+    c['case']['source_context'] = {'refs':[{'path':f'original/source-{i}.cpp'} for i in range(9)]}
+    before = copy.deepcopy(c)
+    c['research_guidance_version'] = 1
+    request = build_prompt(c)
+    body = json.loads(request['messages'][1]['content'])
+    assert len(body['input']['source_access']['package_source_refs']) == 3
+    assert body['input']['source_access']['omitted_package_source_refs'] == 6
+    assert 'overrides' in request['messages'][0]['content']
+    assert 'QuestAccept' not in request['messages'][0]['content']
+    parts = split_document(body,request['prompt_version'])
+    assert 'source_access' in parts[0]['input']
+    assert restore_document(*parts) == body
+    system,prefix,live = GeminiProvider._messages(request,stable_case_context=True)
+    assert check_wire(system,prefix+live) <= 20000
+    c.pop('research_guidance_version')
+    assert c == before
+    assert 'source_access' not in json.loads(old['messages'][1]['content'])['input']
+
+
+def test_long_package_paths_do_not_expand_catalog():
+    c = context();c['case']['source_context'] = {'refs':[{'path':'x'*701}]}
+    result = source_access(c)
+    assert result['package_source_refs'] == [] and result['omitted_package_source_refs'] == 1
+
+
+def test_bad_namespace_gets_controller_feedback_without_budget_side_effect(tool_case):
+    class Wrong(Adapter):
+        async def generate(self,config,request,**kwargs):
+            body = json.loads(request['messages'][1]['content'])
+            if body['task'] != 'investigate_one_step':
+                return await super().generate(config,request,**kwargs)
+            return ProviderResponse({'assessment':None,'observation':'Search the existing source.',
+                'next':{'kind':'tool','operation':'source.find_text','arguments':{
+                    'source_refs':['src/not-a-package-reference.cpp'],'text':'Start',
+                    'case_sensitive':True,'offset':0,'limit':10}}},'fixture',100,50)
+    loop = loop_for(tool_case,Wrong());run(loop,steps=4)
+    before = BudgetManager(tool_case[0]).snapshot(*CASE).state
+    result = run(loop,steps=1)
+    saved = state(result)
+    assert saved['hypotheses']['H1']['notes'][-1]['code'] == 'TOOL_SOURCE_NOT_DECLARED'
+    with PackageReader(result.package) as reader:
+        c = json.loads(reader.read_bytes(saved['active']['context_ref']))
+    assert 'package_source_refs' in c['previous_rejection_details']['requirement']
+    assert c['previous_rejection_details']['validation_path'] == '/next/arguments/source_refs'
+    assert BudgetManager(tool_case[0]).snapshot(*CASE).state == before
+    assert PackageValidator().validate(result.package).valid
+
+
+def test_nested_recall_is_executed_without_new_research_charge(tool_case):
+    class Recall(Adapter):
+        async def generate(self,config,request,**kwargs):
+            body = json.loads(request['messages'][1]['content'])
+            if body['task'] != 'investigate_one_step':
+                return await super().generate(config,request,**kwargs)
+            self.calls.append(body)
+            return ProviderResponse({'assessment':None,'observation':'Read recorded evidence.',
+                'next':{'kind':'recall','arguments':{'evidence_refs':['E000001'],'page':0}}},
+                'fixture',100,50)
+    adapter = Recall();loop = loop_for(tool_case,adapter)
+    run(loop,steps=4)
+    before = BudgetManager(tool_case[0]).snapshot(*CASE).state
+    result = run(loop,steps=1)
+    saved = state(result)
+    assert saved['hypotheses']['H1']['invalid_responses'] == 0
+    assert BudgetManager(tool_case[0]).snapshot(*CASE).state == before
+    with PackageReader(result.package) as reader:
+        ref = saved['hypotheses']['H1']['notes'][-1]['llm_ref']
+        call = json.loads(reader.read_bytes(ref))
+        assert call['outcome']['document']['next'] == {'kind':'recall','evidence_refs':['E000001'],'page':0}
+        assert call['outcome']['normalization']['rules'] == ['unwrap_recall_arguments:/next']
+    assert PackageValidator().validate(result.package).valid