diff --git a/CLAUDE.md b/CLAUDE.md
index b76440e..caef987 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -28,6 +28,19 @@ External World → Sense(state) → { newState, workflow? } → Workflow → Log
 
 
 
+### Sense State Persistence
+
+Each sense's state is persisted as a JSON file at `data/senses/<name>.json` (relative to the nerve root, typically `~/.uncaged-nerve/`).
+
+| Event | Behavior |
+|-------|----------|
+| **Worker start** | Read `state.json`; if missing or corrupt, use `initialState` from the sense module |
+| **Compute success** | Write new state atomically (write-temp + rename), then update in-memory state |
+| **Compute failure** | State unchanged (both disk and memory) |
+| **Daemon restart** | State restored from last successful write |
+
+State files are written atomically (temp file + rename) to prevent corruption on crash.
+
 ## Language & Paradigm
 
 ### Functional-first
diff --git a/packages/core/src/sense.ts b/packages/core/src/sense.ts
index 19ceb3e..0ba02a1 100644
--- a/packages/core/src/sense.ts
+++ b/packages/core/src/sense.ts
@@ -8,7 +8,7 @@ export type SenseInfo = {
   throttle: number | null;
   timeout: number | null;
   /** Declarative schedule (`interval` / `on`) for this sense (derived from nerve.yaml). */
-  triggers: string[];
+  triggers: ReadonlyArray<string>;
 };
 
 /**
diff --git a/packages/daemon/src/sense-runtime.ts b/packages/daemon/src/sense-runtime.ts
index 6b38303..e5af5c3 100644
--- a/packages/daemon/src/sense-runtime.ts
+++ b/packages/daemon/src/sense-runtime.ts
@@ -1,5 +1,5 @@
-import { mkdirSync, readFileSync, writeFileSync } from "node:fs";
-import { dirname } from "node:path";
+import { existsSync, mkdirSync, readFileSync, renameSync, writeFileSync } from "node:fs";
+import { dirname, join } from "node:path";
 
 import type { Result, SenseComputeFn, WorkflowTrigger } from "@uncaged/nerve-core";
 import { err, isPlainRecord, ok } from "@uncaged/nerve-core";
@@ -14,16 +14,22 @@ export type SenseRuntime = {
 
 export function readState(statePath: string, initialState: unknown): unknown {
   try {
+    if (!existsSync(statePath)) return initialState;
     const raw = readFileSync(statePath, "utf8");
     return JSON.parse(raw);
-  } catch {
+  } catch (e) {
+    const msg = e instanceof Error ? e.message : String(e);
+    process.stderr.write(`[sense-runtime] warning: failed to read state from "${statePath}": ${msg} — using initialState\n`);
     return initialState;
   }
 }
 
 export function writeState(statePath: string, state: unknown): void {
-  mkdirSync(dirname(statePath), { recursive: true });
-  writeFileSync(statePath, JSON.stringify(state, null, 2));
+  const dir = dirname(statePath);
+  mkdirSync(dir, { recursive: true });
+  const tmp = join(dir, `.${Date.now()}.tmp`);
+  writeFileSync(tmp, JSON.stringify(state, null, 2));
+  renameSync(tmp, statePath);
 }
 
 /**
@@ -86,8 +92,8 @@ export async function executeCompute(
       ? await Promise.race([computePromise, timeoutPromise])
       : await computePromise;
 
-    runtime.state = result.state;
     writeState(runtime.statePath, result.state);
+    runtime.state = result.state;
 
     return ok(result);
   } catch (e) {