The runtime persists per-workspace state (`.auth_token`,
`.platform_inbound_secret`, `.mcp_inbox_cursor`) under `/configs` —
the workspace-EC2 mount path. Inside a container that's writable,
agent-owned. Outside a container, `/configs` either doesn't exist or
isn't writable by an unprivileged user.
The default broke the external-runtime path (`pip install
molecule-ai-workspace-runtime` + `molecule-mcp` on a Mac/Linux
laptop). First heartbeat tries to persist `.platform_inbound_secret`
and crashes:
[Errno 30] Read-only file system: '/configs'
The heartbeat thread logs and dies. Workspace flips offline within
a minute. Operator sees no actionable error.
Adds workspace/configs_dir.py — single resolution point with a tiered
fallback:
1. CONFIGS_DIR env var, if set — explicit operator override
(preserves existing tests + custom deployments verbatim).
2. /configs — if it exists AND is writable. In-container default;
unchanged behavior for every prod workspace.
3. ~/.molecule-workspace — created with mode 0700 so per-file 0600
perms aren't undermined by a world-readable parent.
Migrates the four readers (platform_auth, platform_inbound_auth,
mcp_cli, inbox) to call configs_dir.resolve() instead of
inlining `Path(os.environ.get("CONFIGS_DIR", "/configs"))`.
Existing tests that assert the old `/configs`-as-default contract
updated to assert the new contract: when CONFIGS_DIR is unset, path
resolves to a writable location — `/configs` if present, fallback
otherwise. Tests skip the fallback branch on hosts that DO have a
writable `/configs` (CI containers).
Verified the original repro is fixed: with no CONFIGS_DIR set on
macOS, configs_dir.resolve() returns ~/.molecule-workspace, the dir
exists, and writes succeed.
Test suite: 1454 passed, 3 skipped, 2 xfailed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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