No product-build way to relocate the daemon runtime directory when %LOCALAPPDATA% has a capability-SID ACE

[tmonestudio]

Summary

On Windows the daemon/CLI coordination endpoint is created under
%LOCALAPPDATA%, resolved by SHGetFolderPathW(CSIDL_LOCAL_APPDATA) with no
override in a product build. If that ancestry carries a capability-SID ACE with
mutation rights — common on real machines once packaged apps are installed — the
binary cannot start at all, and there is no supported way to point it elsewhere.

The only relocation hook, CBM_TEST_DAEMON_RUNTIME_PARENT, is compiled out
unless CBM_ENABLE_TEST_SEAMS is defined, so the test binary starts fine while
the product binary does not.

Environment

• Windows 11 Pro 10.0.26200, single user, non-domain.
• Working build: main @ 7d6cdb23 + local cc56d509.
• Failing build: current main, built 2026-08-12.

Observed

codebase-memory-mcp: secure daemon endpoint could not be created
codebase-memory-mcp: secure CLI coordination could not be created (endpoint)

Every invocation path fails, including config list, so the settings surface is
unreachable. Independent of CBM_CACHE_DIR: with the cache on a clean
volume-root path the cache check passes and the endpoint failure remains.

Walking the ancestry with the same predicate as
win_private_directory_tree_secure, the only rejected entries under
%LOCALAPPDATA% are a single capability SID:

C:\Users\<user>\AppData        S-1-15-3-...  mask=0x000D0152  inherit_only=false
C:\Users\<user>\AppData\Local  S-1-15-3-...  mask=0x000D0152  inherit_only=false

0x000D0152 includes WRITE_DAC, WRITE_OWNER and DELETE. We are not
asking you to trust that — we agree it is a real tamper vector. Note it is not a
Windows default: C:\Users\Default\AppData\Local has no such ACE. It arrived
with an installed application, and it is present on AppData, Local,
Roaming and LocalLow.

Requests, in order of preference

1. A product-supported override for the runtime parent directory — a config
   key or environment variable, validated by the same
   win_private_directory_tree_secure. The operator picks a path with clean
   ancestry; the check keeps its full strength. This is the one that unblocks us
   without weakening anything.
2. Name the offending path in the endpoint error. The cache failure prints
   ipc_validation_detail and is immediately actionable; the endpoint failure
   prints neither the path nor the ACE, so diagnosing it took reading
   src/daemon/ipc.c.
3. Document the required DACL shape for the runtime and cache directories,
   so operators can provision one deliberately instead of discovering it from a
   rejection.

Cache directory: works, with a caveat worth documenting

Our cache lives on a secondary data volume (46.5 GB; the system volume has 31.8
GB free, so relocating is not an option). F:\IndexadorData\... is rejected for
an inherited Authenticated Users → Modify from the volume root — correctly, we
think. Putting the cache directly under the volume root passes, since the
tool then owns the final directory's DACL and the only ancestor is the root
itself. That is a useful and non-obvious property; documenting it would save
others the same investigation.

Offer

We have the working and failing binaries side by side and an 823-project cache.
Happy to run any diagnostic build.

[DeusData]

Thank you @tmonestudio. Confirmed on current main: main_daemon_endpoint_new() reads only CBM_TEST_DAEMON_RUNTIME_PARENT under CBM_ENABLE_TEST_SEAMS, while the other product endpoint paths call cbm_daemon_bootstrap_endpoint_new(NULL). A product binary therefore has no supported runtime-parent override, and relocating CBM_CACHE_DIR does not move the daemon rendezvous.

#1576 targets this gap without relaxing the private-directory validation. This is routed as a high-priority Windows/security compatibility bug. The PR itself first needs to be unstacked from #1561 so its runtime-only diff can be reviewed cleanly. Thank you for supplying both the failing security condition and a fail-closed design.

[DeusData]

Thank you for this, @tmonestudio. Walking the ancestry with the same predicate as win_private_directory_tree_secure and coming back with the exact capability SID and mask=0x000D0152 removed all the guesswork, and your check that C:\Users\Default\AppData\Local carries no such ACE settled whether this was a Windows default or something an installed app left behind.

Re-confirmed and unchanged: the daemon runtime-directory parent is not overridable in a product build. The only override, CBM_TEST_DAEMON_RUNTIME_PARENT, is read inside #ifdef CBM_ENABLE_TEST_SEAMS in main_daemon_endpoint_new(), so it is compiled out of shipped binaries — the test binary starts and yours cannot, exactly as you described.

A binary that cannot even run config list on an ordinary machine is an operability blocker, and this is a top item for tonight's v0.10.5, which is being prepared for precisely that class of issue. Sorry that you had to read src/daemon/ipc.c to learn why it refused; naming the offending path in the endpoint error is part of the same work.