tools.read = false in opencode.json makes all zen free-tier models fail with "free tier can only be used from within OpenCode" #51315

Environment

• opencode 1.18.29 and 1.18.32, both affected
• Windows 11 x64
• Built-in opencode provider (zen Console), free-tier models
• No custom agents, no plugins, no permissions config

What happens

With this in a project's opencode.jsonc:

{
  "$schema": "https://opencode.ai/config.json",
  "tools": {
    "read": false
  }
}

every request to every zen free-tier model fails with:

Error from provider (Console): OpenCode's free tier can only be used from within OpenCode

The request comes from opencode itself. What changes is the tools array: with read disabled, the request sent to zen no longer contains it, and the free-tier gate rejects it as if it came from outside opencode. The gate runs on zen's side and I can't read its code, but the 9router maintainers bisected the same behaviour from their side: decolua/9router#4101 documents that free-tier requests with 0-3 tools, or missing the required tool set that includes read, get refused, while requests carrying it get 200.

Reproduction

1. Empty project directory, opencode.jsonc containing only the config above.
2. opencode run -m opencode/mimo-v2.6-flash-free "Reply with exactly: ok" gives the 403.
3. Delete the "tools" block, or just the "read": false line, and the same request succeeds.

Same client, same machine, same session throughout:

So disabling edit/write/apply_patch is harmless. The only thing that matters is read.

What I expected

The gate should not care which tools the config enables, or the tools.* option should say it breaks the free tier. As it stands, a supported, documented config option quietly kills every free model for the whole project, and the error message blames the client for something the user configured.

Why I disable it

I use the lineage-mcp server for file operations. Its read/write tools report line-level external changes and append the AGENTS.md instruction files from parent directories up the stack once per session. The built-in tools do neither. So "tools": { "read": false, ... } is not some exotic setup for me, it's the documented way to get the built-ins out of the way.

If I have the option to remove the read tool, why would removing it be a free-tier violation? A request with fewer tools is still a request from opencode.

Related

• policy: deny shell * on custom agent breaks free tier with "can only be used from within OpenCode" #50627 (deny shell permission on a custom agent, same gate, same error)
• subagents: explore agent denied free tier can only be used from within OpenCode while running inside the CLI — general works with identical models #49723 (explore subagent tripped by the same check while general works)
• [Bug] "OpenCode's free tier can only be used from within OpenCode" error when using Custom Agents #50081, Server (1.18.31): Free tier zen models fail - User-Agent not forwarded to zen API #49756 (same error, other request-shape triggers)

Workaround

Re-enable read in projects where you want free models. That's it.