core: instruction initialization blocked by unavailable sources (Maximum call stack size exceeded)

[seiya4444]

Summary

Every session fails to start with Instructions.InitializationBlocked: Instruction initialization blocked by unavailable sources: core/instructions. The root cause is a RangeError: Maximum call stack size exceeded (stack overflow) in the core/instructions source activation code. This affects both the shared background service and --standalone mode.

Environment

• opencode version: 2.0.11 (latest, channel=latest)
• OS: Windows 11 Pro, Build 22631, x64
• Terminal: Windows Terminal / PowerShell 7
• Shell: C:\WINDOWS\system32\cmd.exe / PowerShell 7
• Install/channel: npm global install (@opencode/cli@2.0.11)
• Active plugins: postgres (local plugin at ~/.config/opencode/plugins/postgres), herdr-agent-state.js, i-have-adhd.js

Reproduction

1. Install OpenCode v2.0.11 via npm (npm install -g @opencode/cli)
2. Run opencode (or opencode --standalone)
3. Create a new session
4. Session immediately fails with the error below

Expected Behavior

Session should start normally and process messages.

Actual Behavior

Every session fails immediately on creation. The logs show:

WARN  "failed to activate instruction source"
      cause="Cause([Die(RangeError: Maximum call stack size exceeded.)])"

ERROR "Failed to drain Session"
      cause="Instructions.InitializationBlocked: Instruction initialization
      blocked by unavailable sources: core/instructions
          at FE (chunk-1sa5rvxc.js:30:42285)
          at InstructionState.observe (chunk-1sa5rvxc.js:32:1283)
          at InstructionState.prepare (chunk-vyhk950s.js:365:2744)
          at SessionRunner.prepareContext (chunk-vyhk950s.js:365:2321)
          at SessionRunner.advanceToStep (chunk-vyhk950s.js:365:2583)
          at SessionRunner.drain (chunk-24mc5jhy.js:24:2279)"

This happens consistently across:

• Multiple project directories
• Both shared service and --standalone mode
• After service restart (opencode service stop + restart)
• After full computer restart

Additional Context

• The core/instructions source crashes with infinite recursion before it can be marked as available, which then blocks session initialization.
• Workaround attempted: opencode --standalone — same error occurs.
• Config file is minimal (~/.config/opencode/opencode.json), AGENTS.md is only 756 bytes (16 lines).
• Full log available at ~/.local/share/opencode/log/opencode.log (~45MB).

[holny]

Found the likely culprit — ancestorDirectories (packages/core/src/config/plugin/instruction.ts:133) recurses on dirname(start) and only terminates when start === stop. When the two paths don't string-match exactly (separator or case differences are easy to hit on Windows), the walk blows past stop, and since dirname("C:\\") keeps returning "C:\\" the recursion never bottoms out — hence the RangeError. That die is caught at :123, which marks the core/instructions source unavailable, so every session then fails with Instructions.InitializationBlocked — matching your trace exactly.

Fix is to bound the walk at the filesystem root instead of relying on the string comparison reaching stop. PR shortly.

[VimWei]

The same issue, completely unusable.

OpenCode v2.0.10 - 2.0.14 via npm

[VimWei]

1. OpenCode can be executed successfully in the following directories.
   C:\Apps
   C:\Users\chenw\Downloads\Documents
   C:\Apps\AOE
   C:\Apps\test\

2. The following steps were executed, resulting in the previous error.
   C:\Apps\mdxpress
   c:\Apps\dachu-commit

The analysis reveals a difference between these two scenarios: if previous sessions exist (e.g., opencode 1.x, but an upgrade to 2.x was performed during the initial run), an error occurs. If no previous sessions are present, the process runs normally.

[VimWei]

Narrowed down: triggered by legacy 1.x session data, not by version

Not a duplicate — adding evidence to the existing diagnosis.

Project dir	Has 1.x session?	Result
C:\Apps	no	✅ works
C:\Apps\AOE	no	✅ works
C:\Apps\test	no	✅ works
C:\Users<me>\Downloads\Documents	no	✅ works
C:\Apps\mdxpress	yes	❌ InitializationBlocked
C:\Apps\dachu-commit	yes	❌ InitializationBlocked

• Version is NOT the variable: 2.0.10 and 2.0.14 both reproduce.
• Directory location is NOT the variable: C:\Apps works, C:\Apps\test works.
• 2.0.14 worked on very first run, before legacy sessions were loaded.
  Every new session after that fails.

Hypothesis: one of start/stop in ancestorDirectories comes from the
working-directory field migrated from 1.x sessions, and it doesn't
string-match the current path (trailing slash / case / separator style).

@holny — a root-filesystem guard alone is not enough. When start and stop
are on different branches, the walk should return [] rather than the full
ancestor chain, otherwise the crash becomes a wrong result.

[holny]

Gentle nudge — this has been open for a week with green checks and no review. The fix is small: ancestorDirectories walks iteratively with an explicit filesystem-root bound instead of recursing until two path strings compare equal, which overflows the stack on Windows when the forms drift. Covered by a dedicated regression test where stop is never an ancestor. Happy to rebase or adjust if anything needs changing.

[Diambiru]

Additional confirmation from Windows 11 Home 10.0.26220: this still reproduces on OpenCode 2.0.16 and 2.0.19.

• Both versions logged the same instruction-source activation failure:
  failed to activate instruction source
Cause([Die(RangeError: Maximum call stack size exceeded.)])
• On 2.0.16, a subsequent session attempt failed with:
  Instructions.InitializationBlocked: Instruction initialization blocked by unavailable sources: core/instructions
  with InstructionState.observe -> InstructionState.prepare -> SessionRunner.prepareContext.
• That failed 2.0.16 session recorded zero cost and zero input/output tokens.
• On 2.0.19, the server was running opencode-cli.exe serve --service. During the diagnostic period, POST /api/location/reload completed successfully while the same RangeError was logged. No provider call was made during this 2.0.19 diagnostic.
• The 2.0.19 check did not establish a subsequent Instructions.InitializationBlocked / session-preparation failure.
• Read-only checks found no AGENTS.md at ~/.config/opencode, the checked home directory, the workspace root, or its checked parent directories.

I have not isolated the triggering instruction source or confirmed that a case-variant location is the cause in this environment, so I am only reporting the observed symptom/version persistence here.

This extends the confirmed affected-version range beyond 2.0.14 to at least 2.0.19.

[rutexd]

I'm having pretty same issue. v2.0.20. Its happening very random to me.

The issue somehow appears randomly and sometimes resolved when im killed running server (kill opencode.exe)
In some cases it looks to be depending on project (new session creating fine on empty projects and vice-versa: running fine on existing session and not creating on new projects)
Sometimes the full package reinstall helps and sometimes not...
I thought maybe it was a conflict with opencode v1 and tried to clean all caches and all configs which i could only find, but this doesn't looks to help much.

Something is very strange happening here.

[jack5github]

Since updating to v2.0.21, this has begun to affect every single folder I attempt to use OpenCode in, making the program completely unusable.