fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… by ryangamerdev · Pull Request #15516 · anomalyco/opencode · GitHub

Issue for this PR

Closes #6633
Related: #7261, #14237, #6279, #15117

Type of change

Bug fix
New feature
Refactor / code improvement
Documentation

What does this PR do?

When opencode exits, MCP servers that spawn child processes (e.g. chrome-devtools-mcp spawning Chrome) leave those grandchild processes orphaned. The MCP SDK's StdioClientTransport.close() only signals the direct child — it has no way to reach processes further down the tree. These orphans accumulate across sessions and cause a 3-5 second shutdown delay because the SDK times out waiting on a server that is blocked waiting on its own children.

Additionally, concurrent opencode sessions sharing the same MCP server config clash on shared state. With chrome-devtools-mcp for example, each new session tries to take over the same browser instance, killing the previous session's MCP service in the process.

Before calling client.close(), we now walk the full descendant tree of each local MCP server transport using pgrep -P and SIGTERM every descendant. With its children already gone, the MCP server exits immediately and the SDK close completes without hitting its timeout. Skipped on Windows where pgrep is not available.

Also sets OPENCODE_PID in process.env at startup alongside the existing OPENCODE=1. MCP server configs can reference {env:OPENCODE_PID} to keep each session's MCP services fully independent — each session gets its own isolated browser instance and they no longer interfere with each other.

Example config:

"chrome-devtools": {
  "type": "local",
  "command": [
    "npx", "-y", "chrome-devtools-mcp@latest",
    "--userDataDir={env:HOME}/.cache/chrome-devtools-mcp/{env:OPENCODE_PID}"
  ]
}

Changes:

mcp/index.ts: descendants() walks the process tree via pgrep -P BFS; dispose handler SIGTERMs all descendants before SDK close
index.ts, e2e-local.ts: set process.env.OPENCODE_PID = String(process.pid)

How did you verify your code works?

Started opencode with chrome-devtools-mcp configured with --userDataDir={env:HOME}/.cache/chrome-devtools-mcp/{env:OPENCODE_PID}. Confirmed Chrome launched. Exited opencode — exit was immediate (previously 3-5 seconds). pgrep -fa chrome-devtools-mcp returned nothing. Ran two concurrent sessions and confirmed each used an isolated profile directory with no SingletonLock conflicts.

Screenshots / recordings

N/A — terminal process, no UI changes.

Checklist

I have tested my changes locally
I have not included unrelated changes in this PR

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found the following potentially related PRs:

Related PRs (not duplicates)

PR fix(web): dispose idle MCP server instances to prevent process accumulation #15326 - "fix(web): dispose idle MCP server instances to prevent process accumulation"
- Addresses similar process cleanup concerns for MCP servers
PR fix: resolve memory leaks and zombie processes from missing cleanup handlers #13186 - "fix: resolve memory leaks and zombie processes from missing cleanup handlers"
- Related to zombie process cleanup and proper cleanup handlers
PR fix(mcp): Fix memory leaks in OAuth transport and process cleanup #9145 - "fix(mcp): Fix memory leaks in OAuth transport and process cleanup"
- Involves MCP process cleanup and memory leak resolution

These PRs address related issues with process cleanup and MCP server management, but none appear to be duplicates of PR #15516. The current PR is uniquely focused on:

Killing orphaned MCP child processes via process tree traversal (pgrep -P)
Exposing OPENCODE_PID for session isolation in MCP configs

No duplicate PRs found

…tdown

lgtm tysm

One more note about this one, the reason I didn't add OPENCODE_SESSION_ID to be exported is because the point specifically where MCP services are initiated is BEFORE a session has been initiated. Setting/exporting SessionID for use with the MCP services would be a major overhaul compared to how it's done today, and not add much to any value in my opinion. I can see the point of setting OPENCODE_SESSION_ID as an environment variable once a session is established so that it can be used in the session or for agents or other use cases, but that is solving a different problem and different area of the code than this PR, so to keep it clean this was focused on the MCP services.

…… (#15516)

anomalyco#15516)

…… (#15516)

ryangamerdev requested a review from adamdotdevin as a code owner March 1, 2026 01:50

github-actions Bot added the contributor label Mar 1, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…

0cfcf0e

…tdown

ryangamerdev force-pushed the fix/mcp-orphan-cleanup-and-pid branch from 64e0d60 to 0cfcf0e Compare March 1, 2026 01:52

github-actions Bot mentioned this pull request Mar 1, 2026

📊 AI CLI 工具社区动态日报 2026-03-01 rollysys/agents-radar#7

Closed

nexxeln approved these changes Mar 1, 2026

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nexxeln merged commit c4c0b23 into anomalyco:dev Mar 1, 2026
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ryangamerdev deleted the fix/mcp-orphan-cleanup-and-pid branch March 1, 2026 18:53

ryangamerdev mentioned this pull request Mar 1, 2026

v1.1.6 still has memory bloat - heap not released + MCP orphan processes #7261

Closed

nexxeln mentioned this pull request Mar 3, 2026

opencode run: MCP child processes not terminated on exit (orphan leak) #15808

Closed

Grappeggia referenced this pull request in teamslop/slopcode Mar 4, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…

dcad05a

…… (#15516)

OSSDeveloper mentioned this pull request Mar 20, 2026

[FEATURE]: chrome-devtools MCP tab reuse for agentic sessions #18409

Closed

1 task

iMaxTomas mentioned this pull request Apr 12, 2026

[FEATURE]: Allow disabling built-in MCP servers (chrome-devtools, morphllm-fast-apply) #22188

Closed

coleleavitt mentioned this pull request Apr 21, 2026

fix/memory 20695 coleleavitt/opencode#5

Merged

xywsxp pushed a commit to xywsxp/opencode that referenced this pull request Apr 24, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

3c72dc8

anomalyco#15516)

Rwanbt pushed a commit to Rwanbt/unifia that referenced this pull request May 5, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

c92d1f4

anomalyco#15516)

This was referenced May 10, 2026

Local stdio MCP servers leak processes on disconnect / replace / rollback #26714

Closed

fix: terminate local stdio mcp processes on disconnect / replace / rollback #26715

Closed

AIALRA-0 pushed a commit to AIALRA-0/opencode-turn-engine that referenced this pull request Jun 10, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

63cbf9b

anomalyco#15516)

AIALRA-0 pushed a commit to AIALRA-0/opencode-turn-engine that referenced this pull request Jun 10, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

f297756

anomalyco#15516)

avion23 pushed a commit to avion23/opencode that referenced this pull request Jun 10, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

10402dd

anomalyco#15516)

Rwanbt pushed a commit to Rwanbt/unifia that referenced this pull request Jun 14, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… (

44a0356

anomalyco#15516)

MarsQiu007 referenced this pull request in MarsQiu007/openNovel Jul 31, 2026

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…

fcb3a6f

…… (#15516)

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… by ryangamerdev · Pull Request #15516 · anomalyco/opencode · GitHub

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fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… - #15516

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…#15516
nexxeln merged 1 commit into
anomalyco:devfrom
gignit:fix/mcp-orphan-cleanup-and-pid

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fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… by ryangamerdev · Pull Request #15516 · anomalyco/opencode · GitHub

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fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu… - #15516

fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…#15516nexxeln merged 1 commit intoanomalyco:devanomalyco/opencode:devfrom gignit:fix/mcp-orphan-cleanup-and-pidgignit/opencode:fix/mcp-orphan-cleanup-and-pidCopy head branch name to clipboard

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ryangamerdev commented Mar 1, 2026

Issue for this PR

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Related PRs (not duplicates)

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fix: kill orphaned MCP child processes and expose OPENCODE_PID on shu…#15516
nexxeln merged 1 commit into
anomalyco:devfrom
gignit:fix/mcp-orphan-cleanup-and-pid