diff --git a/packages/paperclip-runner/runner/crates/runner-core/src/durable/state.rs b/packages/paperclip-runner/runner/crates/runner-core/src/durable/state.rs
index 1201c84a4c7..92f35e6db21 100644
--- a/packages/paperclip-runner/runner/crates/runner-core/src/durable/state.rs
+++ b/packages/paperclip-runner/runner/crates/runner-core/src/durable/state.rs
@@ -2052,6 +2052,9 @@ fn validate_semantic_tool_input_digest(
 }
 
 pub(crate) fn redact_text(input: &str) -> String {
+    // Cutting a secret first leaves an unmatchable plaintext fragment.
+    let redacted = redact_sensitive_text_values(input);
+    let input = redacted.as_str();
     let (bounded, truncated) = if input.len() > 4096 {
         let boundary = input
             .char_indices()
@@ -2063,7 +2066,7 @@ pub(crate) fn redact_text(input: &str) -> String {
     } else {
         (input, false)
     };
-    let mut redacted = redact_sensitive_text_values(bounded);
+    let mut redacted = bounded.to_owned();
     if truncated {
         redacted.push_str("…[truncated]");
     }
@@ -4263,6 +4266,42 @@ mod tests {
         );
     }
 
+    #[test]
+    fn identity_redaction_precedes_multibyte_truncation() {
+        let prefix = "MC4CAQAwBQYDK2VwBCIEIA";
+        let body = format!("{prefix}{}", "A".repeat(64 - prefix.len()));
+        let key = format!("-----BEGIN PRIVATE KEY-----\n{body}\n-----END PRIVATE KEY-----\n");
+        // Give only this subprocess the key; do not race other tests' environment.
+        if std::env::var_os("PAPERCLIP_IDENTITY_TRUNCATION_TEST").is_none() {
+            let output = std::process::Command::new(std::env::current_exe().unwrap())
+                .args([
+                    "--exact",
+                    "durable::state::tests::identity_redaction_precedes_multibyte_truncation",
+                    "--nocapture",
+                ])
+                .env("PAPERCLIP_IDENTITY_TRUNCATION_TEST", "1")
+                .env("PAPERCLIP_AGENT_PRIVATE_KEY", &key)
+                .output()
+                .unwrap();
+            assert!(
+                output.status.success(),
+                "{}{}",
+                String::from_utf8_lossy(&output.stdout),
+                String::from_utf8_lossy(&output.stderr)
+            );
+            return;
+        }
+        for material in [&body, &key] {
+            let input = format!("{}{material}", "é".repeat(2025));
+            let output = redact_text(&input);
+            assert!(!output.contains(prefix));
+            assert!(output.contains("[REDACTED]"));
+            assert!(output.len() <= 4096);
+            let persisted = sanitize_value(&json!({"text": input}));
+            assert!(!persisted.to_string().contains(prefix));
+        }
+    }
+
     #[test]
     fn diagnostic_redaction_still_bounds_retained_text() {
         let output = redact_text(&format!("token=secret-value {}", "x".repeat(4_096)));
diff --git a/server/src/__tests__/agent-identity.test.ts b/server/src/__tests__/agent-identity.test.ts
index 97dbdb5daf6..dcdbf1189b2 100644
--- a/server/src/__tests__/agent-identity.test.ts
+++ b/server/src/__tests__/agent-identity.test.ts
@@ -172,6 +172,28 @@ describe("agent cryptographic identity", () => {
     }
   }, 60_000);
 
+  it("persists ordinary stdout and stderr endings after settling the identity buffer", async () => {
+    const agent = await oldAgent();
+    await db.update(agents).set({ adapterType: "process", adapterConfig: {
+      command: process.execPath, cwd: directory,
+      args: ["-e", "process.stdout.write('safe-'); process.stderr.write('safeM');"],
+    } }).where(eq(agents.id, agent.id));
+    const heartbeat = heartbeatService(db);
+    try {
+      const run = await heartbeat.invoke(agent.id, "on_demand", {}, "manual");
+      await drainHeartbeatRunsToQuiescence(db, heartbeat);
+      const finished = await heartbeat.getRun(run!.id);
+      expect(finished?.status).toBe("succeeded");
+      expect(finished?.stdoutExcerpt).toMatch(/safe-$/);
+      expect(finished?.stderrExcerpt).toMatch(/safeM$/);
+      const lines = (await heartbeat.readLog(run!.id)).content.trim().split("\n").map(line => JSON.parse(line));
+      expect(lines.filter(line => line.stream === "stdout").map(line => line.chunk).join("")).toContain("safe-");
+      expect(lines.filter(line => line.stream === "stderr").map(line => line.chunk).join("")).toContain("safeM");
+    } finally {
+      await drainHeartbeatRunsToQuiescence(db, heartbeat);
+    }
+  }, 60_000);
+
   it("disaster recovery retains identity; both development seed modes omit it and mint fresh keys", async () => {
     const agent = await oldAgent();
     const original = await agentIdentityService(db).ensureAgentIdentity(companyId, agent.id);
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 43c7295da77..6a47fc592e7 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -23446,9 +23446,9 @@ export function heartbeatService(
 
         const currentUserRedactionOptions =
           await getCurrentUserRedactionOptions();
-        const onLog = async (stream: "stdout" | "stderr", chunk: string) => {
+        const appendIdentityRedactedLog = async (stream: "stdout" | "stderr", chunk: string) => {
           const sanitizedChunk = compactRunLogChunk(
-            redactCurrentUserText(identityRedactor.chunk(stream, chunk), currentUserRedactionOptions),
+            redactCurrentUserText(chunk, currentUserRedactionOptions),
           );
           if (stream === "stdout")
             stdoutExcerpt = appendExcerpt(stdoutExcerpt, sanitizedChunk);
@@ -23521,6 +23521,8 @@ export function heartbeatService(
             },
           });
         };
+        const onLog = (stream: "stdout" | "stderr", chunk: string) =>
+          appendIdentityRedactedLog(stream, identityRedactor.chunk(stream, chunk));
         if (runScopedMentionedSkillKeys.length > 0) {
           await onLog(
             "stdout",
@@ -25169,7 +25171,7 @@ export function heartbeatService(
           adapterResult = identityRedactor.redact(adapterResult);
           for (const stream of ["stdout", "stderr"] as const) {
             const tail = identityRedactor.finish(stream);
-            if (tail) await onLog(stream, tail);
+            if (tail) await appendIdentityRedactedLog(stream, tail);
           }
           if (instructionSave) adapterResult.resultJson = { ...adapterResult.resultJson, instructionSave };
           adapterResult = applyWorkspaceRestoreFailure(adapterResult);