feat(developer): add opencode w/ some custom agents (#68)

Author: feltnerm

modules/home-manager/feltnerm/ai.nix

@@ -0,0 +1,168 @@
+{
+  config,
+  lib,
+  ...
+}:
+let
+  cfg = config.feltnerm.developer.ai;
+in
+{
+  # Only apply when developer and AI are enabled
+  config = lib.mkIf cfg.enable {
+
+    services = {
+      ollama = {
+        # fails on aarm64-darwin
+        enable = lib.mkDefault false;
+      };
+    };
+
+    programs = {
+      # OpenCode CLI configuration and agents
+      opencode = {
+        enable = lib.mkDefault true;
+        agents = {
+          explain = ''
+            ---
+            temperature: 0.3
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+            You are an expert explainer of complex technical concepts.
+            Your goal is to break down complicated ideas into clear, concise, and easily understandable explanations.
+            Use analogies and examples where appropriate.
+          '';
+          deep_thinker = ''
+            ---
+            temperature: 0.1
+            maxSteps: 15
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+            You are a methodical and rigorous expert problem solver.
+            For every request, you must first create a detailed, numbered step-by-step reasoning plan before arriving at a final, thoroughly checked answer.
+            Show your work.
+          '';
+          code_reviewer = ''
+            ---
+            description: Reviews code for quality and best practices.
+            temperature: 0.05
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+
+            You are a meticulous, objective Code Reviewer.
+            Analyze the provided code for quality, performance, maintainability, and architectural fit.
+            Provide a clear summary, then a line-by-line critique.
+            Your tone must be constructive and professional.
+          '';
+          security_auditor = ''
+            ---
+            description: Audits and reviews code for security best practices.
+            temperature: 0.0
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+
+            You are an expert Security Auditor specializing in OWASP Top 10 and language-specific vulnerabilities.
+            Review the code for security flaws, buffer overflows, injection risks, and inadequate authentication/authorization.
+            If a flaw is found, provide a fix and a detailed explanation of the vulnerability.
+          '';
+          technical_writer = ''
+            ---
+            description: Review and create documentation.
+            temperature: 0.5
+            ---
+
+            You are a professional Technical Writer.
+            Your goal is to generate clear, well-structured, and accurate documentation, comments, or explanations for the code or concept provided.
+            Use appropriate Markdown headings and formatting.
+          '';
+          quick_thinker = ''
+            ---
+            description: Get a simple answer fast.
+            temperature: 0.4
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+
+            You are a fast, high-level consultant.
+            Provide concise, immediate feedback or a quick solution path, focusing on speed and simplicity.
+            Limit your response to 3-5 sentences.
+          '';
+          creative_thinker = ''
+            ---
+            description: Suggest new ideas and approaches.
+            temperature: 0.8
+            tools:
+              write: false
+              edit: false
+              patch: false
+            ---
+
+            You are a generative ideator and lateral thinker.
+            Your primary goal is to provide at least three diverse and unconventional options for the user's request.
+            Focus on architectural possibilities, creative solutions, and innovative approaches.
+            Be bold.
+          '';
+        };
+        settings = {
+          model = lib.mkDefault "github-copilot/gpt-5";
+          small_model = lib.mkDefault "github-copilot/claude-sonnet-4";
+          agent = {
+            build = { };
+            plan = {
+              model = lib.mkDefault "github-copilot/claude-sonnet-4.5";
+            };
+            explore = {
+              model = lib.mkDefault "github-copilot/gpt-4o";
+            };
+            general = {
+              model = lib.mkDefault "github-copilot/gpt-5";
+            };
+            explain = {
+              mode = "primary";
+              model = lib.mkDefault "github-copilot/gpt-5";
+              reasoningEffort = lib.mkDefault "high";
+              textVerbosity = lib.mkDefault "low";
+            };
+            deep_thinker = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/claude-sonnet-4.5";
+            };
+            code_reviewer = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/claude-sonnet-4.5";
+            };
+            security_auditor = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/gpt-5";
+            };
+            technical_writer = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/claude-sonnet-4.5";
+            };
+            quick_thinker = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/claude-sonnet-4";
+            };
+            creative_thinker = {
+              mode = "subagent";
+              model = lib.mkDefault "github-copilot/gpt-4o";
+            };
+          };
+        };
+      };
+    };
+  };
+}

modules/home-manager/feltnerm/developer.nix

@@ -42,6 +42,10 @@ let
   };
 in
 {
+  imports = [
+    ./ai.nix
+  ];
+
   options.feltnerm.developer = {
     enable = lib.mkEnableOption "developer";
     codeHome = lib.mkOption {
@@ -74,13 +78,6 @@ in
 
   config = lib.mkIf cfg.enable {
 
-    services = {
-      ollama = lib.mkIf cfg.ai.enable {
-        # fails on aarm64-darwin
-        enable = lib.mkDefault false;
-      };
-    };
-
     programs = {
       zsh.initContent = lib.mkIf (
         config.programs.zsh.enable && config.programs.fzf.enable
@@ -106,10 +103,6 @@ in
         };
       };
 
-      opencode = lib.mkIf cfg.ai.enable {
-        enable = lib.mkDefault true;
-      };
-
       nixvim = {
         extraPlugins = [ ];
         plugins = {