{
  den,
  modules,
  inputs,
  ...
}:
{
  modules.pi-coding = {
    homeManager =
      { pkgs, config, ... }:
      {
        programs.pi-coding-agent = {
          enable = true;
          extraPackages = [
            pkgs.nodejs
            # pkgs.lean-lsp-mcp
          ];
          settings = {
            "litellm" = {
              "providers" = {
                "litellm" = {
                  "displayName" = "scuggo";
                  "baseUrl" = "https://ai-proxy.fwds.scug.io";
                  "apiKey" = "$SCUG_IO_API_KEY";
                  "compat" = {
                    "sendSessionAffinityHeaders" = true;
                  };
                };
              };
              "skills" = {
                "enabled" = true;
              };
              "compat" = {
                "sendSessionAffinityHeaders" = true;
              };
            };
            "mcp" = {
              "enabled" = true;
            };
            "uiMode" = "fullscreen";
            "showCacheMissNotices" = true;
            "vstack" = {
              "extensionManager" = {
                "config" = { };
              };
            };
            packages = [
              # "npm:@odinlayer/pi-provider-litellm"
              "npm:pi-provider-litellm"
              # Web search / content extraction (opencode-crawlberg + opencode-html-to-markdown equivalent)
              "npm:pi-web-access"
              # Local document parsing / OCR (opencode-xberg equivalent)
              "npm:pi-docparser"
              # "npm:@gotgenes/pi-permission-system"
              "npm:@vanillagreen/pi-extension-manager"
              # "npm:@vanillagreen/pi-qol"
              "npm:pi-vitals"
              "npm:pi-spark"
              "npm:pi-caveman"
              "npm:@tmustier/pi-usage-extension"
              "npm:@heyhuynhgiabuu/pi-pretty"
              "npm:pi-lens"
              # "npm:pi-lean-ctx"
              # "npm:@rohaquinlop/pi-deepseek-cache"
              "npm:pi-cache-optimizer"
              "npm:pi-opencode-go-cache"
            ];
          };
          context = ''
                                    Core Directive: precise execution, strict safety, long-term solutions.
                                    1. Standards: hard fail unless overridden; files <=300 lines (refactor if exceeded); no hardcoding — config/env/consts only; no defaults — fail on missing config; no legacy/shims/auto-migrations, assume clean state; root fixes only, no cosmetic patches (report unrelated bugs).
                                    2. Safety: never run destructive ops (rm, reset --hard, deletions) without explicit prior approval; respect sandbox mode (ro/write), request approval if blocked; new code = creative, existing code = minimal deltas (no style/rename drift).
                                    3. Tools: todowrite for multi-step — exactly one in_progress, update on completion; rg for search; outputs truncated (~256 lines/10KB), read large files in chunks (<250 lines); edit = trust tool, no re-read, no added headers/comments; build/test/lint before yielding, yield only after todowrite done.
                                    4. Communication: AGENTS.md governs — deepest file wins, user prompt overrides; 1-sentence next-action preamble before any tool call; final output GFM with clickable file refs (src/main.ts:50), no file://, technical/dense/impersonal.

                                    [CORE TOOLING DOCTRINE]
                                    - Files: read truncates at 2000 lines/50KB (use offset/limit); write creates/overwrites/auto-parents; edit = smallest unique oldText, merge nearby, never include huge unchanged regions. Never cat/echo/tee/sed -i/head/tail for file content.
                                    - Search: rg -n for text; grep tool (glob filter) for content; find tool for glob discovery only.
                                    - Navigation: symbol_search → module_report → read_symbol/read_enclosing; never find + manual parsing.
                                    - Diagnostics: lens_diagnostics (delta=this turn, all=session, full=project-wide before done); lsp_diagnostics before builds.
                                    - Context: recall_context(id) to recover compressed/expired/truncated content.
                                    - bash: only for git/nix/builds/scripts/network/system mgmt; set timeout for long ops.
                                    - CRITICAL: never find on /nix/store — unpruned walk locks up execution; ls known paths, ask user for unknown paths. ABSOLUTE.
            												- You have a web-search tool. Use it sparingly but reach for it in situations where info isnt directly known. (i.e, "common problem" -> get from memory, think hard if needed, "hard problem that isnt in your training data or request for you to read docs for a lib or program" -> search online)
                        						- Searching for anything (including with wildcards ("/nix/store/*/**" or others)) isnt permitted at all. You must find paths inside the project, such a result/
          '';
        };

        # pi-vitals config
        home.file.".pi/agent/powerline.json" = {
          text = builtins.toJSON {
            leftSegments = [
              "pi"
              "separator"
              "model"
              "thinking"
              "ext_status"
              "separator"
              "path"
              "git"
              "separator"
              "token_total"
              "token_in"
              "token_out"
              "cache_read"
              "cache_write"
            ];
            rightSegments = [
              "separator"
              "cost"
              "context_pct"
            ];
            icons = {
              pi = "π";
              model = "◈";
              thinking = "🧠";
              folder = "📁";
              repo = "📦";
              git = "⎇";
              tokens = "⊛";
              input = "↑";
              output = "↓";
              cacheRead = "↙";
              cacheWrite = "↗";
              contextPct = "◫";
              cost = "$";
              separator = "│";
            };
            colors = {
              pi = "accent";
              model = "#d787af";
              path = "#00afaf";
              git = "success";
              gitDirty = "warning";
              gitClean = "success";
              thinking = "muted";
              context = "dim";
              contextWarn = "warning";
              contextError = "error";
              cost = "text";
              tokens = "muted";
              separator = "dim";
            };
            segmentOptions = {
              path = {
                mode = "basename";
              };
              git = {
                showBranch = true;
                showStaged = true;
                showUnstaged = true;
                showUntracked = true;
              };
              context_pct = {
                showAutoIcon = false;
              };
            };
          };
        };
        home.file.".pi/agent/auth.json" = {
          text = builtins.toJSON {
            "opencode-go" = {
              "type" = "api_key";
              "key" = "$OPENCODE_GO_API_KEY";
            };
            "opencode" = {
              "type" = "api_key";
              "key" = "$OPENCODE_GO_API_KEY";
            };
          };
        };

        # Cache/routing compat overrides (provider-level minimal)
        home.file.".pi/agent/models.json" = {
          text = builtins.toJSON {
            providers = {
              "opencode-go" = {
                compat = {
                  supportsLongCacheRetention = true;
                };
              };
            };
          };
        };

        # Restrict providers to a subset of their built-in models.
        # Filter config: ~/.pi/agent/model-filters.json (see below).
        home.file.".pi/agent/extensions/model-filter.ts" = {
          source = ./model-filter.ts;
        };
    
        # Show model cost in status bar
        home.file.".pi/agent/extensions/model-cost.ts" = {
          source = ./model-cost.ts;
        };
    
        # Model filter config: per-provider filters applied by model-filter.ts
        home.file.".pi/agent/model-filters.json" = {
          text = builtins.toJSON {
            providers = {
              # opencode: only free models (all cost zero)
              opencode = {
                freeOnly = true;
              };
            };
          };
        };

        # pi-web-access config: raw results, no curator / no AI summarising
        home.file.".pi/web-search.json" = {
          text = builtins.toJSON {
            workflow = "none";
          };
        };

        # pi-spark config
        home.file.".pi/agent/spark.json" = {
          text = builtins.toJSON {
            editor = {
              spinner = "tildes";
            };
            footer = false;
            presets = {
              "scuggo" = {
                provider = "litellm";
                model = "Ornith-1.0-9B";
                thinkingLevel = "medium";
              };
              "claude" = {
                provider = "anthropic";
                model = "claude-opus-4-8";
                thinkingLevel = "high";
              };
              "gpt" = {
                provider = "openai-codex";
                model = "gpt-5.5";
                thinkingLevel = "medium";
              };
            };
          };
        };
      };
  };
}