No initialize handshake. No session state. Restart or load-balance the server between calls — clients never notice. tools/list answers with CacheableResult fields (ttlMs: 3600000, cacheScope: "private") so hosts can cache the tool list, and unknown versions are rejected with -32022 naming the supported list — never silently swallowed.
Handshake-era clients (Claude Desktop, VS Code, Codex) keep working unchanged. Both eras, one process — with a test that runs them mixed against one server instance.
python
reported = engine.policy_for(spec) # what get-policy says outcome = engine.execute(spec, params) # what actually ran
assert reported["preopens"] == \
outcome.report.security_baseline["preopens"]
How we verified it
Fresh venv, plain pip install ephemora-cell, 13/13 acceptance checks against the published wheel: both MCP eras, version negotiation, policy/witness agreement, legacy compatibility unchanged. Bonus finding: the same echo call consumed identical fuel (21143) across two different installs on different machines — the determinism claim held in the wild.
Try it bash
pip install ephemora-cell
ephemora-cell-mcp # bundled clock + echo; --tools-dir for your own
Feedback welcome — repo, issues and the full CHANGELOG are at [https://github.com/MichaelS1011/ephemora-cell](https://github.com/MichaelS1011/ephemora-cell)