cli: update skipped - installation method not found on Windows npm install #51604

Description

opencode update aborts on Windows with update skipped: installation method not found even though @opencode/cli is installed globally via npm. Retry a minute later detects npm and succeeds, so detection appears flaky / timeout-sensitive.

Failed run acdd81ed (2.0.11 → 2.0.18 available): all 5 method probes spawned at 06:42:36, WARN at 06:42:47 (~11s) with no per-probe error detail. Successful retry a7971fc1 completed the same 5 probes in ~2s, then npm install --global --force @opencode/cli@2.0.18 → Upgrade complete, now on 2.0.18.

Log (~/.local/share/opencode/log/opencode.log):

timestamp=2026-09-27T06:42:36.197Z level=INFO run=acdd81ed message="spawning process" command=npm args="[\"list\",\"-g\",\"--depth=0\",\"@opencode/cli\"]" cwd=undefined role=cli
timestamp=2026-09-27T06:42:36.213Z level=INFO run=acdd81ed message="spawning process" command=pnpm args="[\"list\",\"-g\",\"--depth=0\",\"@opencode/cli\"]" cwd=undefined role=cli
timestamp=2026-09-27T06:42:36.220Z level=INFO run=acdd81ed message="spawning process" command=bun args="[\"pm\",\"ls\",\"-g\"]" cwd=undefined role=cli
timestamp=2026-09-27T06:42:36.343Z level=INFO run=acdd81ed message="spawning process" command=yarn args="[\"global\",\"list\"]" cwd=undefined role=cli
timestamp=2026-09-27T06:42:36.365Z level=INFO run=acdd81ed message="spawning process" command=vp args="[\"list\",\"-g\",\"--json\",\"@opencode/cli\"]" cwd=undefined role=cli
timestamp=2026-09-27T06:42:47.404Z level=WARN run=acdd81ed message="update skipped: installation method not found" role=cli

Notes: yarn/vp not installed, pnpm reports no match, bun pm ls -g lists unrelated packages — same on the successful retry, so not the cause. Prior 2.0.3 → 2.0.11 update on 2026-09-20 used npm successfully. Workaround: opencode update --method npm. Suggest logging per-probe exit code/stderr/timing and/or increasing probe timeout on Windows npm+nvm setups.

Not a duplicate of #46493 (scoop false-positive: scoop sorted first and scoop list header match; I have no scoop, error is not found not wrong-method) nor #49660 (pacman-managed /usr/bin install that can never be detected; mine is npm-managed and retry succeeds).

Plugins

None as plugins; config has skills path + 2 disabled MCP servers (chrome-devtools, dataverse-ranjith-preview).

OpenCode version

2.0.18 (failure occurred on 2.0.11 attempting 2.0.11 → 2.0.18)

Steps to reproduce

1. On Windows with npm-global install at C:\nvm4w\nodejs\opencode (npm list -g shows @opencode/cli@2.0.11, npm root -g = C:\nvm4w\nodejs\node_modules via nvm4w).
2. Run opencode update (2.0.11 → 2.0.18 available).
3. Observe Using method never appears; log shows WARN update skipped: installation method not found.
4. Run opencode update again ~1 minute later — it detects npm and upgrades to 2.0.18.

Screenshot and/or share link

No response

Operating System

Microsoft Windows NT 10.0.26200.0 (cmd /c ver: Microsoft Windows [Version 10.0.26200.9457])

Terminal

TERM=xterm-256color; Shell COMSPEC=C:\Windows\system32\cmd.exe