The per-session record store is now the ONLY cwd mechanism. Deleted:
- env.cwd_owner stamping + prev_owner threading (terminal_tool): the
shared env no longer carries ownership metadata at all
- _resolve_command_cwd's env/prev_owner params: resolution is
workdir > session record > config/override default
- file_tools._live_cwd_if_owned + _get_live_tracking_cwd: path
resolution never consults the shared env's live cwd
- file_tools._last_known_cwd + _remember_last_known_cwd +
_last_known_cwd_for: the #26211 preserved-anchor registry is
subsumed by the session record, which never lived on the env and
therefore cannot be lost to env cleanup. The _get_file_ops
stale-cache rescue now writes the record instead.
- env recreation (both _get_file_ops and terminal_tool) seeds the
fresh env from override > session record > config
Why no transition fallback: the legacy state was process-local and
in-memory exactly like the record store — after a restart both start
empty, and within a running process every legacy write site has been
dual-writing the record since step 1. There is no populated-legacy/
empty-record state to fall back for.
Tests updated to drive the record store instead of the deleted
mechanism; the cross-session isolation suite now asserts the same
behavior contracts (no leak, cd isolation, #26211 persistence)
against the new architecture, plus a new "session C inherits nothing"
case that the old ownership guard could not express.
After a successful write_file or patch, update the stored read
timestamp to match the file's new modification time. Without this,
consecutive edits by the same task (read → write → write) would
false-warn on the second write because the stored timestamp still
reflected the original read, not the first write.
Also renames the internal tracker key from 'file_mtimes' to
'read_timestamps' for clarity.
Track file mtime when read_file is called. When write_file or patch
subsequently targets the same file, compare the current mtime against
the recorded one. If they differ (external edit, concurrent agent,
user change), include a _warning in the result advising the agent to
re-read. The write still proceeds — this is a soft signal, not a
hard block.
Key design points:
- Per-task isolation: task A's reads don't affect task B's writes.
- Files never read produce no warning (not enforcing read-before-write).
- mtime naturally updates after the agent's own writes, so the warning
only fires on external changes, not the agent's own edits.
- V4A multi-file patches check all target paths.
Tests: 10 new tests covering write staleness, patch staleness,
never-read files, cross-task isolation, and the helper function.
