Fix local agent runtime context

AGENTS.md

@@ -304,6 +304,7 @@ Pacotes de sessao e desktop usados diretamente pelos configs:
 Pacotes relevantes para trabalho/dev presentes no estado atual:
 
 - `unstable.codex`
+- `opencode` empacotado via Home Manager com `libstdc++.so.6` no `LD_LIBRARY_PATH`
 - `vscode`
 - `clang-tools`
 - `nodejs`
@@ -562,6 +563,7 @@ Itens que um agente deve verificar antes de mexer:
 - `pactl` e necessario para `configs/waybar/switch_sink.sh`.
 - `Home Assistant` local e `~/.config/secrets/ha_token` sao dependencias externas do controle de ar.
 - `open-webui` depende do `ollama` configurado no host.
+- `OLLAMA_CONTEXT_LENGTH` esta em `32768`; reduzir para 8k quebra prompts grandes de agentes com schemas de ferramentas.
 
 ### Home Assistant / Codex status
 

home/ltadeu6.nix

@@ -1,5 +1,17 @@
 { config, pkgs, lib, ... }:
 
+let
+  opencodeWithLibstdcxx = pkgs.symlinkJoin {
+    name = "opencode";
+    paths = [ pkgs.unstable.opencode ];
+    nativeBuildInputs = [ pkgs.makeWrapper ];
+    postBuild = ''
+      wrapProgram $out/bin/opencode \
+        --prefix LD_LIBRARY_PATH : ${lib.makeLibraryPath [ pkgs.stdenv.cc.cc.lib ]}
+    '';
+  };
+in
+
 {
   home.username = "ltadeu6";
   home.homeDirectory = "/home/ltadeu6";
@@ -244,7 +256,7 @@
     direnv
     unzip
     unstable.codex
-    unstable.opencode
+    opencodeWithLibstdcxx
     claude-code
     zip
     file-roller

hosts/Nixos/configuration.nix

@@ -388,8 +388,8 @@ in {
       acceleration = "cuda";
       host = "[::]";
       environmentVariables = {
-        # Lower default context to keep KV cache smaller (faster + more likely to stay on GPU).
-        OLLAMA_CONTEXT_LENGTH = "8192";
+        # Agent CLIs send large prompts with tool schemas; 8k truncates tool-use instructions.
+        OLLAMA_CONTEXT_LENGTH = "32768";
       };
       loadModels = [
         "gemma4:e4b"