The legacy code used 'try: rp.relative_to(cwd); return True; except ValueError: pass'
to check path containment. Python 3.9+ has Path.is_relative_to() which returns
bool directly, eliminating the silent-swallow try/except entirely.
This is a NON-SLIMING migration: the function's behavior is unchanged (still
returns True/False), the test of path containment is the same, but the
implementation no longer relies on bare except+pass. No logging added, no
silenced error, just a cleaner API.
Audit: mcp_client INTERNAL_SILENT_SWALLOW 3 -> 2.
Re-read lines 462-540 (The Broad-Except Distinction), lines 625-690 (Re-Raise
Patterns), and the AI Agent Checklist. CRITICAL anti-sliming protocol:
Phase 8 = mcp_client silent-swallow + UNCLEAR (6 sites):
- 5 INTERNAL_SILENT_SWALLOW sites (bare-except or except+pass patterns)
- 1 UNCLEAR site
Plus 3 nested BC cleanup (1 _search_file in py_find_usages_result + 2 trace
in derive_code_path_result).
RULES (anti-sliming):
- NO narrowing+logging (narrow + sys.stderr.write / logging.error = STILL violation)
- NO silent recovery (except: pass = SILENT_SWALLOW violation)
- MUST use full Result[T] propagation up to a true drain point
- Logging is NOT a drain (per user's principle 2026-06-17)
Initial v3.1 spec + plan for the delta thickening of v3. v3.1 is the canonical v3 review at depth (>=3,800 LOC main review) with a chunking strategy that v3 lacked. Adds 3 new top-level sections (YAML avoidance, agent context-window, fine-tuning). Load-bearing principle: v3.1 is standalone-readable without consulting v2.3 or v3.
Added web_search_result, fetch_url_result, get_ui_performance_result inside Result Variants region.
The 3 legacy functions now delegate to their _result variants.
Audit: mcp_client BC 8 -> 3 (sites 6,7,8 migrated). Remaining 3 sites are
nested functions (1 in py_find_usages_result._search_file + 2 in derive_code_path_result.trace)
which are inherent to the implementation and will be addressed in Phase 8.
Added derive_code_path_result inside Result Variants region.
Legacy derive_code_path (str) now delegates to it. The nested trace
function is now inside the _result variant; its inner try/except
captures ErrorInfo correctly.
Phase 7 = mcp_client Batch E: 8 more INTERNAL_BROAD_CATCH sites
- L1338 py_get_hierarchy, L1359 py_get_docstring
- L1383 derive_code_path, L1418 trace
- L1452 get_tree
- L1535 web_search, L1561 fetch_url, L1580 get_ui_performance
Target: mcp_client BC 9 -> 1 after Batch E (the _search_file nested try/except
is separate from these 8 Batch E sites; will be classified/fixed in Phase 8).
Phase 5 Batch C (8 INTERNAL_BROAD_CATCH sites in mcp_client.py):
Added _result variants in the Result Variants region:
- ts_cpp_get_definition_result
- ts_cpp_get_signature_result
- ts_cpp_update_definition_result
- py_get_skeleton_result (uses ASTParser)
- py_get_code_outline_result (uses outline_tool, NOT ASTParser)
- py_get_symbol_info_result (returns Result[tuple[str, int]])
- py_get_definition_result (uses ast.parse directly)
- py_update_definition_result (delegates to set_file_slice_result)
Each legacy string-returning function now delegates to its _result variant;
the try/except Exception is REMOVED from the legacy function.
The _result variants for py_* functions use ast.parse directly (matching
the existing implementation pattern). py_get_code_outline_result uses
outline_tool (not ASTParser as originally assumed).
Phase 4 test loosened (BC<=24, total MIG<=72) to allow Batch C overshoot.
Audit: mcp_client BC 24 -> 16. Total MIG 72 -> 64.
Re-read lines 462-540 (The Broad-Except Distinction). Same migration
pattern as Phase 3 Batch A: each legacy string-returning tool function
delegates to its _result variant. The try/except Exception in the
legacy function is REMOVED; the new Result variant captures ErrorInfo
with kind=INTERNAL and the original exception.
Phase 4 = mcp_client Batch B: 8 INTERNAL_BROAD_CATCH sites (lines 473-593)
- L473 get_git_diff
- L492 ts_c_get_skeleton, L509 ts_c_get_code_outline, L523 ts_c_get_definition
- L537 ts_c_get_signature, L555 ts_c_update_definition
- L576 ts_cpp_get_skeleton, L593 ts_cpp_get_code_outline
Target: mcp_client BC 32 -> 24 after Batch B.
Added set_file_slice_result(Result[str]) inside the Result Variants region.
Legacy set_file_slice (str) now delegates to set_file_slice_result.
Audit: mcp_client BC count 33 -> 32 (Batch A complete: -8 sites).
Added get_file_slice_result(Result[str]) inside the Result Variants region.
Legacy get_file_slice (str) now delegates to get_file_slice_result.
Audit: mcp_client BC count 34 -> 33.
Added get_file_summary_result(Result[str]) inside the Result Variants region.
Legacy get_file_summary (str) now delegates to get_file_summary_result.
Audit: mcp_client BC count 35 -> 34.
Added edit_file_result(Result[str]) inside the Result Variants region.
Legacy edit_file (str) now delegates to edit_file_result.
Audit: mcp_client BC count 36 -> 35.
Legacy list_directory (str) now delegates to list_directory_result (Result[str]).
The try/except Exception is REMOVED.
Audit: mcp_client BC count 38 -> 37.
Legacy search_files (str) now delegates to search_files_result (Result[str]).
The try/except Exception in the legacy function is REMOVED; the new Result
variant captures ErrorInfo (kind=INTERNAL with original exception).
Audit: mcp_client BC count 39 -> 38.
Legacy _resolve_and_check (Path|None, str tuple) now delegates to
_resolve_and_check_result (Result[Path]). The try/except Exception in the
legacy function is REMOVED; the new Result variant captures the structured
ErrorInfo (kind=INVALID_INPUT for path errors, kind=PERMISSION for
allowlist denials). Error messages are propagated via ui_message().
Updated tests/test_py_struct_tools.py::test_mcp_dispatch_errors to accept
the new 'permission' ErrorKind string instead of the legacy 'ACCESS DENIED'
substring (the new format is more descriptive).
Audit: mcp_client BC count 40 -> 39.
ed