diff --git a/README.md b/README.md
index b72a0a72..429b4acb 100644
--- a/README.md
+++ b/README.md
@@ -153,6 +153,43 @@ Web/Mobile Clients
 - **Gateway**: WebSocket server for remote clients
 - **Hub**: Agent lifecycle and event distribution
 
+## Time
+
+Super Multica now uses **message-level timestamp injection** for time awareness.
+Instead of placing dynamic time text in the system prompt, user turns are stamped at runtime.
+
+```mermaid
+flowchart TD
+  A[Incoming turn] --> B{Entry point}
+  B -->|Desktop/Gateway/Cron/Subagent| C[AsyncAgent.write]
+  B -->|Heartbeat poll| D[AsyncAgent.write injectTimestamp=false]
+  C --> E{Already stamped or has 'Current time:'?}
+  E -->|Yes| F[Keep original message]
+  E -->|No| G[Prefix: [DOW YYYY-MM-DD HH:mm TZ]]
+  D --> H[Keep original heartbeat prompt]
+  F --> I[Agent.run]
+  G --> I
+  H --> I
+  I --> J[LLM receives final turn text]
+```
+
+### Injection Matrix
+
+| Path | Runtime call | Timestamp injected? | Notes |
+| --- | --- | --- | --- |
+| Desktop direct chat | `agent.write(content)` | Yes | Default behavior |
+| Gateway/remote chat | `agent.write(content)` | Yes | Same entry path as desktop |
+| `sessions_spawn` child task | `childAgent.write(task)` | Yes | Child turn gets current time context |
+| Cron `agent-turn` payload | `agent.write(cronMessage)` | Yes (guarded) | Skips if message already carries `Current time:` |
+| Heartbeat runner | `agent.write(prompt, { injectTimestamp: false })` | No | Prevents heartbeat prompt matching from breaking |
+| Internal orchestration | `writeInternal(...)` | No | Uses separate internal run path |
+
+### Why this design
+
+- Keeps system prompt cache-stable (no per-turn date churn in system prompt text)
+- Gives the model an explicit "now" reference on each user turn
+- Uses guardrails to avoid double-stamping and heartbeat regressions
+
 ## Scripts
 
 ```bash