Agents web: improve connection stability and terminal reconnection#312189
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Agents web: improve connection stability and terminal reconnection#312189
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osortega
commented
Apr 23, 2026
osortega
commented
- WebSocketClientTransport: fail-fast on send to dead socket with force-close and _closeFired guard to prevent double onClose events
- AgentHostPty: add reconnect() method with 10s hydration timeout and buffer clear before snapshot replay
- AgentHostTerminalService: add reconnectTerminals() scoped by oldClientId, track active ptys with dispose cleanup
- RemoteAgentHostContribution: trigger terminal reconnection on clientId change during reconnect
- Telemetry: add socket/close, socket/sendDropped, socket/visibilityResumed, terminal/recovery events
- Fix isMeasurement on boolean fields in existing telemetry
- WebSocketClientTransport: fail-fast on send to dead socket with force-close and _closeFired guard to prevent double onClose events - AgentHostPty: add reconnect() method with 10s hydration timeout and buffer clear before snapshot replay - AgentHostTerminalService: add reconnectTerminals() scoped by oldClientId, track active ptys with dispose cleanup - RemoteAgentHostContribution: trigger terminal reconnection on clientId change during reconnect - Telemetry: add socket/close, socket/sendDropped, socket/visibilityResumed, terminal/recovery events - Fix isMeasurement on boolean fields in existing telemetry
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Pull request overview
Improves Agents web reliability by making agent-host WebSocket connections fail fast on zombie sockets and enabling reconnection of agent-host-backed terminals after a client reconnect.
Changes:
- Add
AgentHostPty.reconnect()andIAgentHostTerminalService.reconnectTerminals()to rehydrate/replay terminal state after reconnect. - Trigger terminal reconnection from the sessions-side
RemoteAgentHostContributionwhen a connection is re-registered. - Extend sessions telemetry with socket lifecycle + terminal recovery events and adjust boolean classifications.
Show a summary per file
| File | Description |
|---|---|
| src/vs/workbench/contrib/terminal/browser/agentHostTerminalService.ts | Tracks active PTYs per clientId and adds reconnectTerminals() to retarget PTYs to a new connection. |
| src/vs/workbench/contrib/terminal/browser/agentHostPty.ts | Adds reconnect() to resubscribe and replay terminal content after disconnect/reconnect. |
| src/vs/sessions/contrib/remoteAgentHost/browser/remoteAgentHost.contribution.ts | Invokes terminal reconnection when a remote agent host connection’s clientId changes. |
| src/vs/sessions/common/sessionsTelemetry.ts | Adds new telemetry events for socket lifecycle and terminal recovery; fixes boolean field classification. |
| src/vs/platform/agentHost/browser/webSocketClientTransport.ts | Adds send fail-fast behavior and guards to avoid double onClose firing. |
Copilot's findings
- Files reviewed: 5/5 changed files
- Comments generated: 4
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
rzhao271
reviewed
Apr 23, 2026
| if (newConnection) { | ||
| this._agentHostTerminalService.reconnectTerminals(newConnection, oldClientId).then( | ||
| ({ recovered, total }) => { | ||
| if (total > 0) { |
rzhao271
approved these changes
Apr 23, 2026
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