console: free tier rejects a specific existing session and any fork of it, new sessions work #57147

Description

Free-tier models return HTTP 403 FreeTierError for one specific existing session, and for every session forked from it — including an empty fork with 0 messages. Brand-new sessions in the same project, with the same agent and model, work fine at the same moment. The request is rejected before inference (1-2 s, no tokens billed).

Affected session: ses_Ddv16i0l55Ptn7tNW6rUg3wL4n (agent plan, model opencode/deepseek-v4.1-flash-free, Desktop app)
Working session, same project/agent/model: ses_eaad33c23ffenS4T2nmgVFA9uo

OpenCode version

• Desktop app / background service: 2.0.32 (the app auto-updated from 2.0.29 during the session)
• opencode --version on PATH: opencode v2.0.29

Plugins

• Local plugin ~/.config/opencode/plugins/telegram-notify/index.ts (Telegram notifications only; it just calls api.telegram.org)
• MCP server: managed opencode_console

Steps to reproduce

1. Open the affected session (agent plan, model opencode/deepseek-v4.1-flash-free) and send any prompt. It fails immediately with provider.auth / 403 FreeTierError.
2. Create a new session in the same project with the same agent and model, send any prompt. It works.
3. Fork the affected session with the boundary before its first message, so the fork contains 0 messages:
   POST /api/session/ses_Ddv16i0l55Ptn7tNW6rUg3wL4n/fork {"before":"msg_ACMnLTgMFhyO8uSbCKwNFs6lnl"}
   The fork inherits agent and model but has no history.
4. Send any prompt in that empty fork. Same 403 FreeTierError.
5. Fork a working session the same way (0 messages) and send the same prompt. It succeeds.
6. Interleaved A/B a few seconds apart: the empty fork of the affected session fails twice; the empty fork of the working session succeeds.

Fork IDs from the test: empty fork of affected session ses_eaacdd467ffe7DOLmo7WxQXFZ2 (fails), empty fork of working session ses_eaaca25c0ffeIm6xrwEzvSKsDR (succeeds).

Actual behavior

Stored message error:

{"type":"provider.auth","message":"OpenCode's free tier can only be used from within OpenCode. Download it at https://opencode.ai and keep building.","status":403,"response":{"body":"{\"type\":\"error\",\"error\":{\"type\":\"FreeTierError\",\"message\":\"OpenCode's free tier can only be used from within OpenCode. Download it at https://opencode.ai and keep building.\"}}"}}

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

timestamp=2026-10-19T17:12:47.821Z level=ERROR message="Failed to drain Session" cause="AI.Error: OpenCode's free tier can only be used from within OpenCode..." role=server sessionID=ses_Ddv16i0l55Ptn7tNW6rUg3wL4n
timestamp=2026-10-19T17:13:26.224Z level=ERROR message="Failed to drain Session" cause="AI.Error: OpenCode's free tier can only be used from within OpenCode..." role=server sessionID=ses_Ddv16i0l55Ptn7tNW6rUg3wL4n

Expected behavior

A session created and used by the official client keeps working on the free tier, and forking a session does not propagate a rejection.

What I ruled out

• Model: fails with deepseek-v4.1-flash-free and glm-5.3-flash-free. A paid model (opencode/deepseek-v4.1-flash) in the same session gets past the free-tier gate and returns provider.quota "Insufficient account funds", so the request is attributed to the account normally.
• Agent: fails with both plan and build.
• History / context size: an empty fork (0 messages) still fails.
• Session permissions: the affected session carries a saved permission [{"action":"browser","resource":"*","effect":"allow"}]; PATCH /api/session/<id> {"permissions": []} cleared it and the session still failed.
• Timing / flakiness: interleaved A/B seconds apart, fails every time.
• Account / workspace: free models are enabled and available in the workspace, and other free-model sessions in the same project work.

Possible lead: this session was exported (opencode session export ses_Ddv16i0l55Ptn7tNW6rUg3wL4n) and resumed with opencode -s ses_Ddv16i0l55Ptn7tNW6rUg3wL4n on 2026-10-18, the day before it started failing.

Operating System

Windows 11 Home, 10.0.26300 (x64)

Terminal

OpenCode Desktop app (CLI checks run from Windows PowerShell 5.1)