opencode: add mcp module integration

modules/programs/opencode.nix

@@ -16,6 +16,35 @@ let
   cfg = config.programs.opencode;
 
   jsonFormat = pkgs.formats.json { };
+
+  transformMcpServer = name: server: {
+    name = name;
+    value = {
+      enabled = !(server.disabled or false);
+    }
+    // (
+      if server ? url then
+        {
+          type = "remote";
+          url = server.url;
+        }
+        // (lib.optionalAttrs (server ? headers) { headers = server.headers; })
+      else if server ? command then
+        {
+          type = "local";
+          command = [ server.command ] ++ (server.args or [ ]);
+        }
+        // (lib.optionalAttrs (server ? env) { environment = server.env; })
+      else
+        { }
+    );
+  };
+
+  transformedMcpServers =
+    if cfg.enableMcpIntegration && config.programs.mcp.enable && config.programs.mcp.servers != { } then
+      lib.listToAttrs (lib.mapAttrsToList transformMcpServer config.programs.mcp.servers)
+    else
+      { };
 in
 {
   meta.maintainers = with lib.maintainers; [ delafthi ];
@@ -25,6 +54,20 @@ in
 
     package = mkPackageOption pkgs "opencode" { nullable = true; };
 
+    enableMcpIntegration = mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = ''
+        Whether to integrate the MCP servers config from
+        {option}`programs.mcp.servers` into
+        {option}`programs.opencode.settings.mcp`.
+
+        Note: Settings defined in {option}`programs.mcp.servers` are merged
+        with {option}`programs.opencode.settings.mcp`, with OpenCode settings
+        taking precedence.
+      '';
+    };
+
     settings = mkOption {
       inherit (jsonFormat) type;
       default = { };
@@ -147,7 +190,7 @@ in
         Custom themes for opencode. The attribute name becomes the theme
         filename, and the value is either:
         - An attribute set, that is converted to a json
-        - A path to a file conaining the content
+        - A path to a file containing the content
         Themes are stored in {file}`$XDG_CONFIG_HOME/opencode/themes/` directory.
         Set `programs.opencode.settings.theme` to enable the custom theme.
         See <https://opencode.ai/docs/themes/> for the documentation.
@@ -159,13 +202,21 @@ in
     home.packages = mkIf (cfg.package != null) [ cfg.package ];
 
     xdg.configFile = {
-      "opencode/config.json" = mkIf (cfg.settings != { }) {
+      "opencode/config.json" = mkIf (cfg.settings != { } || transformedMcpServers != { }) {
-        source = jsonFormat.generate "config.json" (
+        source =
-          {
+          let
-            "$schema" = "https://opencode.ai/config.json";
+            # Merge MCP servers: transformed servers + user settings, with user settings taking precedence
-          }
+            mergedMcpServers = transformedMcpServers // (cfg.settings.mcp or { });
-          // cfg.settings
+            # Merge all settings
-        );
+            mergedSettings =
+              cfg.settings // (lib.optionalAttrs (mergedMcpServers != { }) { mcp = mergedMcpServers; });
+          in
+          jsonFormat.generate "config.json" (
+            {
+              "$schema" = "https://opencode.ai/config.json";
+            }
+            // mergedSettings
+          );
       };
 
       "opencode/AGENTS.md" = (

tests/modules/programs/opencode/default.nix

@@ -11,4 +11,6 @@
   opencode-mixed-content = ./mixed-content.nix;
   opencode-themes-inline = ./themes-inline.nix;
   opencode-themes-path = ./themes-path.nix;
+  opencode-mcp-integration = ./mcp-integration.nix;
+  opencode-mcp-integration-with-override = ./mcp-integration-with-override.nix;
 }

tests/modules/programs/opencode/mcp-integration-with-override.json

@@ -0,0 +1,27 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "context7": {
+      "enabled": true,
+      "headers": {
+        "CONTEXT7_API_KEY": "{env:CONTEXT7_API_KEY}"
+      },
+      "type": "remote",
+      "url": "https://mcp.context7.com/mcp"
+    },
+    "custom-server": {
+      "enabled": true,
+      "type": "remote",
+      "url": "https://example.com"
+    },
+    "everything": {
+      "command": [
+        "custom-command"
+      ],
+      "enabled": false,
+      "type": "local"
+    }
+  },
+  "model": "anthropic/claude-sonnet-4-20250514",
+  "theme": "opencode"
+}

tests/modules/programs/opencode/mcp-integration-with-override.nix

@@ -0,0 +1,48 @@
+{
+  programs.mcp = {
+    enable = true;
+    servers = {
+      everything = {
+        command = "npx";
+        args = [
+          "-y"
+          "@modelcontextprotocol/server-everything"
+        ];
+      };
+      context7 = {
+        url = "https://mcp.context7.com/mcp";
+        headers = {
+          CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}";
+        };
+      };
+    };
+  };
+
+  programs.opencode = {
+    enable = true;
+    enableMcpIntegration = true;
+    settings = {
+      theme = "opencode";
+      model = "anthropic/claude-sonnet-4-20250514";
+      # User's custom MCP settings should override generated ones
+      mcp = {
+        everything = {
+          enabled = false; # Override to disable
+          command = [ "custom-command" ];
+          type = "local";
+        };
+        custom-server = {
+          enabled = true;
+          type = "remote";
+          url = "https://example.com";
+        };
+      };
+    };
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.config/opencode/config.json
+    assertFileContent home-files/.config/opencode/config.json \
+      ${./mcp-integration-with-override.json}
+  '';
+}

tests/modules/programs/opencode/mcp-integration.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "context7": {
+      "enabled": true,
+      "headers": {
+        "CONTEXT7_API_KEY": "{env:CONTEXT7_API_KEY}"
+      },
+      "type": "remote",
+      "url": "https://mcp.context7.com/mcp"
+    },
+    "disabled-server": {
+      "command": [
+        "echo",
+        "test"
+      ],
+      "enabled": false,
+      "type": "local"
+    },
+    "everything": {
+      "command": [
+        "npx",
+        "-y",
+        "@modelcontextprotocol/server-everything"
+      ],
+      "enabled": true,
+      "type": "local"
+    }
+  }
+}

tests/modules/programs/opencode/mcp-integration.nix

@@ -0,0 +1,36 @@
+{
+  programs.mcp = {
+    enable = true;
+    servers = {
+      everything = {
+        command = "npx";
+        args = [
+          "-y"
+          "@modelcontextprotocol/server-everything"
+        ];
+      };
+      context7 = {
+        url = "https://mcp.context7.com/mcp";
+        headers = {
+          CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}";
+        };
+      };
+      disabled-server = {
+        command = "echo";
+        args = [ "test" ];
+        disabled = true;
+      };
+    };
+  };
+
+  programs.opencode = {
+    enable = true;
+    enableMcpIntegration = true;
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.config/opencode/config.json
+    assertFileContent home-files/.config/opencode/config.json \
+      ${./mcp-integration.json}
+  '';
+}