OpenClaw Issue Digest: Event Loop Starvation and Session State Regressions

The recent 6-hour window of activity in the OpenClaw repository reveals a concerning trend of performance regressions and stability issues, particularly affecting users on Windows and those utilizing the Codex app-server runtime. The most pressing concerns center around event-loop starvation, which is rendering the Gateway unresponsive during common operations, and a series of session-state bugs that lead to silent message loss and permanent thread breakage.

These issues suggest a growing friction between the core Gateway's asynchronous nature and the synchronous demands of certain provider adapters and internal maintenance tasks. As the system scales in complexity—particularly with the introduction of the Codex app-server and advanced memory plugins—the risk of blocking the main Node.js event loop has become a primary failure mode.

Open Issues

Performance and Event-Loop Starvation

Several high-severity reports highlight the Gateway becoming unresponsive due to CPU-bound synchronous work:

• Windows Event-Loop Blocking: Multiple reports (#86815, #86599, #86846) indicate that on Windows, the Gateway's event loop is being blocked for durations ranging from 8 to 83 seconds. This is particularly evident during provider auth pre-warming and local model calls, where RPCs like agents.list can take over 60 seconds to return.
• Context Compaction Stalls: Issue #86358 reports event-loop starvation of ~17 seconds during auto-compaction, causing pending fetch operations (such as Telegram API calls) to time out.
• Usage/Cost Computation: Heavy processing of sessions.usage and sessions.cost is causing dashboard outages and WebSocket disconnects (#86718), with event loop delays reaching nearly 18 seconds.
• Hot-Path Inefficiencies: A cluster of performance issues (#86786, #86787, #86788, #86789, #86790, #86791) identifies repeated synchronous filesystem probes and expensive cloning of the subagent registry and session rows during high-frequency event broadcasts.

Session State and Reliability

Critical bugs are causing sessions to enter unrecoverable states or lose data:

• Permanent Thread Breakage: Issue #86878 describes a severe bug where exec_command stdout leaks into input_image base64 payloads in Codex rollout files. Because these files are replayed on every API call, a single corrupted line permanently breaks the entire thread.
• Session Lock Leaks: Reports #86816 and #86801 highlight session write locks that are not released after timeouts or are mismatched between hold and wait times, leading to SessionWriteLockTimeoutError and permanently dead sessions.
• Silent Message Loss: Subagent completion announcements are failing silently (#86488, #44925), where results are permanently discarded after three rapid retries without a persistent outbox.
• State-Based Deadlocks: Group chat sessions can become stuck in a failed state (#86827), silently dropping all subsequent messages until the sessions.json file is manually edited.

Provider and Integration Regressions

• Codex Runtime Issues: The transition to the Codex app-server has introduced several regressions, including a hardcoded 30s timeout for dynamic tools that breaks enumeration-heavy MCP tools like session_status (#86758), and a lack of execution isolation compared to the old codex-cli backend (#85943).
• OpenRouter Context Overflow: A regression in version 2026.05.22 causes OpenClaw to incorrectly reserve nearly the entire context window for output tokens when using OpenRouter models, leading to immediate overflow errors (#86880).
• Channel-Specific Bugs: Issues include silent /new resets in Mattermost (#86664), duplicate replies in Telegram (#86519), and a failure to handle dmPolicy: "open" in Slack (#86860).

Key Themes

The "Windows Penalty"

There is a stark disparity in performance between macOS and Windows. Whether it is the 8.5s auth phase vs 1.2s on Mac (#86846) or the total event-loop saturation during local model runs (#86599), Windows users are experiencing a significantly degraded version of the software. This suggests that certain filesystem or network operations are behaving synchronously or inefficiently on Windows.

Synchronous Bottlenecks in an Async Core

Across the board, the primary cause of failure is the blocking of the Node.js event loop. From statx infinite loops in plugin discovery (#86780) to heavy JSON serialization during compaction (#86358), the Gateway is frequently performing CPU-intensive work on the main thread. This is leading to a cascading failure where health checks fail, WebSockets disconnect, and integrations time out.

The Fragility of Session Persistence

Session continuity is currently fragile. The system is prone to "splitting" logical conversations into multiple records (#86743) and failing to clear model overrides upon session reset (#86813). The reliance on file-based locks and fingerprints for session integrity is also introducing race conditions (#86804) and permanent deadlocks (#86816).

Action Required

Immediate Attention (Critical)

• Fix Event-Loop Starvation: Prioritize moving CPU-heavy tasks (compaction, usage computation, plugin metadata scanning) to worker threads or implementing setImmediate yields to prevent Gateway outages.
• Resolve Codex Rollout Corruption: Address the base64 leakage in codex-app-server (#86878) to prevent permanent session loss.
• Repair Session Lock Logic: Fix the in-memory lock leak in the embedded run timeout path (#86816) and the PID-reuse bug in stale lock recovery (#86814).

High Priority

• Address Windows Latency: Investigate the specific cause of the 8-10s auth delays and event-loop blocking on Windows to achieve parity with macOS.
• Fix Subagent Announcement Reliability: Implement a persistent outbox for subagent completions (#86488) to ensure results are not silently lost.
• Correct OpenRouter Context Allocation: Fix the max_tokens calculation for OpenRouter providers to resolve the immediate overflow regression (#86880).

Blockers

• Mattermost /new Acknowledgement: Resolve the silent session reset in Mattermost (#86664) as it is currently flagged as a beta blocker.