diff --git a/flake.lock b/flake.lock
index a425f2b..11ce8e3 100644
--- a/flake.lock
+++ b/flake.lock
@@ -348,6 +348,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-tea": {
+      "locked": {
+        "lastModified": 1791260994,
+        "narHash": "sha256-Miqqk/ammqnTUxaoCyvtwoPeLbI1ksFyLxi/CazZpWY=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "151fa4e8ddfdd8dd25d945ad94ed54a13de9f6e4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1773597492,
@@ -422,6 +438,7 @@
         "llm-agents-pinned": "llm-agents-pinned",
         "nixpkgs": "nixpkgs_5",
         "nixpkgs-stable": "nixpkgs-stable",
+        "nixpkgs-tea": "nixpkgs-tea",
         "sops-nix": "sops-nix",
         "try": "try"
       }
diff --git a/flake.nix b/flake.nix
index db1d7c6..517af15 100644
--- a/flake.nix
+++ b/flake.nix
@@ -5,6 +5,8 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     # Stable nixpkgs for pinning packages with bugs in unstable (e.g., git 2.51.x)
     nixpkgs-stable.url = "github:NixOS/nixpkgs/nixos-24.11";
+    # Newer nixpkgs used only for tea (0.16+); main nixpkgs stays older
+    nixpkgs-tea.url = "github:NixOS/nixpkgs/nixos-unstable";
     darwin.url = "github:LnL7/nix-darwin";
     darwin.inputs.nixpkgs.follows = "nixpkgs";
 
@@ -33,6 +35,7 @@
     inputs@{
       self,
       nixpkgs,
+      nixpkgs-tea,
       darwin,
       home-manager,
       llm-agents,
@@ -66,6 +69,9 @@
       # toolchain pinned in kache's rust-toolchain.toml
       overlaysList = [
         kache.overlays.default
+        (final: _prev: {
+          inherit (nixpkgs-tea.legacyPackages.${final.stdenv.hostPlatform.system}) tea;
+        })
       ];
 
       mkPkgs =
diff --git a/modules/home/devtools/ai-tools.nix b/modules/home/devtools/ai-tools.nix
index 4cdc33d..cc0a3a8 100644
--- a/modules/home/devtools/ai-tools.nix
+++ b/modules/home/devtools/ai-tools.nix
@@ -297,12 +297,15 @@ in
 
         settings_file="$HOME/.pi/agent/settings.json"
         mkdir -p "$(dirname "$settings_file")"
-        ${pkgs.nodejs}/bin/node -e "const fs=require('fs'); const path=process.env.HOME+'/.pi/agent/settings.json'; let settings={}; if (fs.existsSync(path)) settings=JSON.parse(fs.readFileSync(path,'utf8')); settings.theme='dark'; settings.defaultProvider='openai-codex'; settings.defaultModel='gpt-5.6-sol'; fs.writeFileSync(path, JSON.stringify(settings, null, 2)+String.fromCharCode(10));"
+        ${pkgs.nodejs}/bin/node -e "const fs=require('fs'); const path=process.env.HOME+'/.pi/agent/settings.json'; let settings={}; if (fs.existsSync(path)) settings=JSON.parse(fs.readFileSync(path,'utf8')); settings.theme='dark'; settings.defaultProvider='openai-codex'; settings.defaultModel='gpt-6.1-sol'; fs.writeFileSync(path, JSON.stringify(settings, null, 2)+String.fromCharCode(10));"
 
         ${lib.getExe llmPkgs.pi} list | ${pkgs.gnugrep}/bin/grep -q '@ff-labs/pi-fff' || \
           ${lib.getExe llmPkgs.pi} install npm:@ff-labs/pi-fff@0.9.4
         ${lib.getExe llmPkgs.pi} list | ${pkgs.gnugrep}/bin/grep -q '@juicesharp/rpiv-ask-user-question' || \
           ${lib.getExe llmPkgs.pi} install npm:@juicesharp/rpiv-ask-user-question@1.20.0
+        # Install pstack once as a package, not as a copied local extension.
+        ${lib.getExe llmPkgs.pi} list | ${pkgs.gnugrep}/bin/grep -Fq 'git:github.com/0xrsydn/pstack-pi@v0.16.0' || \
+          ${lib.getExe llmPkgs.pi} install git:github.com/0xrsydn/pstack-pi@v0.16.0
       fi
     '';
 
diff --git a/pi/extensions/pstack/README.md b/pi/extensions/pstack/README.md
new file mode 100644
index 0000000..6d475e1
--- /dev/null
+++ b/pi/extensions/pstack/README.md
@@ -0,0 +1,79 @@
+# pstack-pi integration
+
+pstack-pi is installed as an external Pi package, not copied into this directory.
+This directory contains documentation only. Do not add an `index.ts` loader while the package is installed.
+
+## Release pin
+
+- Repository: [0xrsydn/pstack-pi](https://github.com/0xrsydn/pstack-pi).
+- Release: [v0.16.0](https://github.com/0xrsydn/pstack-pi/releases/tag/v0.16.0).
+- Annotated tag commit: `2274745528d0bea38ae6ed23f90221e89a6e7c34`.
+- Source: `git:github.com/0xrsydn/pstack-pi@v0.16.0`.
+- Home Manager declaration: [modules/home/devtools/ai-tools.nix](../../../modules/home/devtools/ai-tools.nix).
+
+The activation script installs the exact source when it is missing or differs from the configured release.
+For immediate installation without a system rebuild:
+
+```sh
+pi install git:github.com/0xrsydn/pstack-pi@v0.16.0
+pi list
+```
+
+Restart Pi or run `/reload` after installation.
+
+## Declaration and activation
+
+`pi install` records the package in `~/.pi/agent/settings.json`.
+The package manifest declares `extensions/pstack/index.ts` and its skills separately.
+Pi loads the extension at session startup or reload.
+The extension registers `/setup-pstack` and the `pstack_task` tool without a skill invocation.
+
+`/skill:poteto-mode` loads workflow instructions. It does not activate the extension.
+A session started with `--no-skills` still loads the package extension and exposes `pstack_task` by default.
+Package resource filters, `--no-extensions`, and tool selection can change this behavior.
+No child process runs until a delegation call occurs.
+
+Keep one package declaration for this repository.
+Do not also copy the extension into `~/.pi/agent/extensions/` or this local extension tree.
+Duplicate entry points can register the same command and tool twice.
+
+## Model configuration
+
+Run `/setup-pstack` to customize any of the 17 roles and panel lists.
+Routes are stored in `~/.pi/agent/pstack-models.json` and read on each delegation call.
+Keep personal credentials and provider routes outside the released package.
+
+The local routing choice uses Grok 4.7 for fast roles and the custom Claude bridge for judgment roles.
+The `medium` budget requests `high` thinking.
+These choices are user configuration, not fixed package requirements.
+
+Neither `poteto-agent` nor `general-purpose` has a fixed model.
+Without a role or task model override, bundled agents inherit the active parent model.
+Dotfiles set `openai-codex/gpt-6.1-sol` as the default for new parent sessions.
+Existing sessions keep their selected model until changed through `/model`.
+
+## Release procedure
+
+1. Prepare the version, lockfile, changelog, and migration notes in a pstack-pi pull request.
+2. Run a clean dependency install, typecheck, tests, and package validation.
+3. Merge the reviewed pull request and verify its exact merged commit.
+4. Create an annotated `v<version>` tag on that commit. Never move a published tag.
+5. Publish a GitHub release with notes, the package archive, and `SHA256SUMS`.
+6. Update both source references in the Home Manager activation script to the published tag.
+7. Update this release record and install the new source locally.
+8. Verify the installed source, version, and one active `pstack_task` registration with skills disabled.
+9. Run Nix formatting, parsing, and `nix flake check` before applying the system configuration.
+
+Use Jujutsu for change management. Use Git only for annotated tag operations unsupported by Jujutsu.
+GitHub release publication does not imply npm registry publication.
+Review and authorize `npm publish` separately.
+
+## Validation of v0.16.0
+
+- TypeScript checks and six tests passed against the merged commit.
+- Package version fields agree on `0.16.0`.
+- The annotated release tag points to the tested merged commit.
+- The GitHub release includes a package archive and a SHA-256 checksum file.
+- A startup probe with `--no-skills` found exactly one registered, active `pstack_task`.
+
+See the [package README](https://github.com/0xrsydn/pstack-pi/blob/v0.16.0/README.md) for Pi primitives, routing precedence, and trust limits.