OpenCode fix for Anthropic plans

opencode-anthropic-system-prompt.patch

diff --git a/packages/opencode/src/session/system.ts b/packages/opencode/src/session/system.ts
--- a/packages/opencode/src/session/system.ts
+++ b/packages/opencode/src/session/system.ts
@@ -27,12 +27,12 @@
   }

   export function provider(model: Provider.Model) {
+    if (model.providerID.includes("anthropic") && model.api.id.includes("claude")) return []
     if (model.api.id.includes("gpt-5")) return [PROMPT_CODEX]
     if (model.api.id.includes("gpt-") || model.api.id.includes("o1") || model.api.id.includes("o3"))
       return [PROMPT_BEAST]
     if (model.api.id.includes("gemini-")) return [PROMPT_GEMINI]
-    if (model.api.id.includes("claude")) return [PROMPT_ANTHROPIC]
     return [PROMPT_ANTHROPIC_WITHOUT_TODO]
   }

opencode-fix.nix

{ inputs, ... }:
{
  environment.systemPackages = [
    (inputs.opencode.packages.${pkgs.stdenv.hostPlatform.system}.default.overrideAttrs (old: {
      patches =
        (old.patches or [])
        ++ [
          ./opencode-anthropic-system-prompt.patch
        ];
    }))
  ];
}

awesome

Gist updated.

The initial "fix" allowed me to actually interact with the model at least but it ran into issues calling tools. Turns out someone had patched the actual oauth plugin and I just did it that same way since it was merged anyway.

This actually works with tool calls now and is a good temporary fix until the OpenCode releases the official fix.

Lovely! And now you put my eyes on nixOs as well. Tnx!

... good temporary fix until the OpenCode releases the official fix.

if

I updated this gist for todays block
Patch is based on this PR: anomalyco/opencode#8553

Seems to work so far