Production mining (state.db, 400k-msg window): 60.2% of 104k terminal
calls carry a defensive 'cd X && ' prefix (~925k tokens of pure prefix)
and 2,462 failed calls led with cd — the model cannot see cwd state, so
it re-asserts it on every call and runs pwd/ls diagnostics after
directory changes.
The result dict now includes a 'cwd' field whenever the session cwd
after the command differs from the cwd it started in (cd, pushd,
chained cd). Stable-cwd commands are unchanged (no field, no noise).
Per-command workdir overrides stay transient by contract and never
echo. Schema note added so models learn to trust session cwd instead
of prefixing. Pattern borrowed from crush's <cwd> injection.
realpath comparison avoids false echoes through symlinks; the echo is
wrapped defensively so a backend without .cwd can never break the
result path.
Teknium