diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 91307693a..c87ec24a4 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,5 +1,5 @@
 {
   "Packages/src": "3.21.1",
   "cli/dispatcher": "3.13.2",
-  "cli/project-runner": "3.12.2"
+  "cli/project-runner": "3.12.3"
 }
diff --git a/.uloop/project-runner-pin.json b/.uloop/project-runner-pin.json
index 7cb314ca5..ecd462414 100644
--- a/.uloop/project-runner-pin.json
+++ b/.uloop/project-runner-pin.json
@@ -2,5 +2,5 @@
   "dispatcherArchiveManifest": "2ba03a1e9a191c745a608831820e533aca35c4af0e1e3437005a2314b0ffb6f0  uloop-dispatcher-darwin-arm64.tar.gz\n32f8231a15eb7cffa0f0af19074303d65d52edb1846b1b830f07e9dc41317db0  install.ps1\n3f0e7ad97e94a36d4ff8ef1c4c7bf4e0ffade39bcd65e81aa118af855053264e  install.sh\n4d10628c9d2df08b8f62eb5e0b6645d41e35bcebaf421bb8c8bc6b98ed16636a  uloop-dispatcher-linux-amd64.tar.gz.sha256\n6eda2092bc4adcff771e0f7d1246d86767d2608710e5bddf85b19b3da4cb9d60  install.sh.sha256\n71d7d24ce52115847d09d2732f2b31aec90c7e369868e35bd1316e21cebb9499  uloop-dispatcher-darwin-amd64.tar.gz\naaf016bd9ce46a360bc51cdef0260c88b3a83f5d6c6c944b8b77eaf60efd72ac  uloop-dispatcher-darwin-arm64.tar.gz.sha256\nb0843c9c2ce1f6c14850160da1af4ad833ea5a793a460a1f04d392f3c5e94f8b  uloop-dispatcher-windows-amd64.zip\nc27b15d8f15a2301c79b2faf80f7559e1aa05520123ebf82a59456951d6af41a  uloop-dispatcher-darwin-amd64.tar.gz.sha256\ne97de8d921af3115bfa00544ec69da6136b9cb0e271966f1073777872cd69838  install.ps1.sha256\nf143c0019673cdc40aed8892db5c1efb3f820f74db162243259285c0f689b2b9  uloop-dispatcher-windows-amd64.zip.sha256\nf211fd2a1814f91bd35e222a57cf2e89f36131aece5a655541824ea801a8c237  uloop-dispatcher-linux-amd64.tar.gz",
   "dispatcherReleaseTag": "dispatcher-v3.13.2",
   "minimumDispatcherVersion": "3.0.0-beta.31",
-  "projectRunnerVersion": "3.12.2"
+  "projectRunnerVersion": "3.12.3"
 }
diff --git a/Packages/src/project-runner-pin.json b/Packages/src/project-runner-pin.json
index 7cb314ca5..ecd462414 100644
--- a/Packages/src/project-runner-pin.json
+++ b/Packages/src/project-runner-pin.json
@@ -2,5 +2,5 @@
   "dispatcherArchiveManifest": "2ba03a1e9a191c745a608831820e533aca35c4af0e1e3437005a2314b0ffb6f0  uloop-dispatcher-darwin-arm64.tar.gz\n32f8231a15eb7cffa0f0af19074303d65d52edb1846b1b830f07e9dc41317db0  install.ps1\n3f0e7ad97e94a36d4ff8ef1c4c7bf4e0ffade39bcd65e81aa118af855053264e  install.sh\n4d10628c9d2df08b8f62eb5e0b6645d41e35bcebaf421bb8c8bc6b98ed16636a  uloop-dispatcher-linux-amd64.tar.gz.sha256\n6eda2092bc4adcff771e0f7d1246d86767d2608710e5bddf85b19b3da4cb9d60  install.sh.sha256\n71d7d24ce52115847d09d2732f2b31aec90c7e369868e35bd1316e21cebb9499  uloop-dispatcher-darwin-amd64.tar.gz\naaf016bd9ce46a360bc51cdef0260c88b3a83f5d6c6c944b8b77eaf60efd72ac  uloop-dispatcher-darwin-arm64.tar.gz.sha256\nb0843c9c2ce1f6c14850160da1af4ad833ea5a793a460a1f04d392f3c5e94f8b  uloop-dispatcher-windows-amd64.zip\nc27b15d8f15a2301c79b2faf80f7559e1aa05520123ebf82a59456951d6af41a  uloop-dispatcher-darwin-amd64.tar.gz.sha256\ne97de8d921af3115bfa00544ec69da6136b9cb0e271966f1073777872cd69838  install.ps1.sha256\nf143c0019673cdc40aed8892db5c1efb3f820f74db162243259285c0f689b2b9  uloop-dispatcher-windows-amd64.zip.sha256\nf211fd2a1814f91bd35e222a57cf2e89f36131aece5a655541824ea801a8c237  uloop-dispatcher-linux-amd64.tar.gz",
   "dispatcherReleaseTag": "dispatcher-v3.13.2",
   "minimumDispatcherVersion": "3.0.0-beta.31",
-  "projectRunnerVersion": "3.12.2"
+  "projectRunnerVersion": "3.12.3"
 }
diff --git a/cli/common/clicontract/contract.json b/cli/common/clicontract/contract.json
index dd0184cfd..fa121116a 100644
--- a/cli/common/clicontract/contract.json
+++ b/cli/common/clicontract/contract.json
@@ -1,4 +1,4 @@
 {
   "protocolVersion": 5,
-  "projectRunnerVersion": "3.12.2"
+  "projectRunnerVersion": "3.12.3"
 }
diff --git a/cli/project-runner/CHANGELOG.md b/cli/project-runner/CHANGELOG.md
index e8458b890..6ab108722 100644
--- a/cli/project-runner/CHANGELOG.md
+++ b/cli/project-runner/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## [3.12.3](https://github.com/hatayama/unity-cli-loop/compare/uloop-project-runner-v3.12.2...uloop-project-runner-v3.12.3) (2026-10-29)
+
+
+### Bug Fixes
+
+* Agents now see the Unity main-thread stall notice even when stderr is not a terminal ([#3416](https://github.com/hatayama/unity-cli-loop/issues/3416)) ([eba0ea4](https://github.com/hatayama/unity-cli-loop/commit/eba0ea4804a7be92890891a22f659e4a487ed625))
+* Commands sent while a dialog blocks the Unity Editor now fail fast with MAIN_THREAD_BLOCKED instead of waiting silently ([#3417](https://github.com/hatayama/unity-cli-loop/issues/3417)) ([1dfaeae](https://github.com/hatayama/unity-cli-loop/commit/1dfaeae5ca35a765ff3ffa4e586173d2326eb794))
+* set-game-view-size no longer reports success under the Device Simulator, and --reset removes the size entry it leaves behind ([#3412](https://github.com/hatayama/unity-cli-loop/issues/3412)) ([4ecde68](https://github.com/hatayama/unity-cli-loop/commit/4ecde684f5c2b17f50f8e45b5476c48c4112e085))
+
 ## [3.12.2](https://github.com/hatayama/unity-cli-loop/compare/uloop-project-runner-v3.12.1...uloop-project-runner-v3.12.2) (2026-10-27)