diff --git a/.gitignore b/.gitignore
index 8a9f57c..138bca6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 .superpowers/
 .worktrees/
+/.*/skills/
 .env*
 !.env.example
 .output/
diff --git a/README.md b/README.md
index 45e1456..5b01d48 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,9 @@ nix develop -c pnpm install --frozen-lockfile
 cp .env.example .env.local
 ```
 
+The Nix development shell installs Hallmark's agent skill for the supported
+local agent targets.
+
 Set `TWITTER_RELAY_BASE_URL` in `.env.local` for Vite development, and set
 `BIRD_PROFILE_NAME` when the relay has multiple profiles. Export the same
 values in the process environment before `start` or `test:live`:
diff --git a/flake.lock b/flake.lock
index 8e8f6d5..2366b86 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,6 +1,78 @@
 {
   "nodes": {
+    "agent-skills-nix": {
+      "inputs": {
+        "home-manager": "home-manager",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1783839654,
+        "narHash": "sha256-rn5DkeQ9PBaJTZl9juBtPnVawyN4B83tyz1VpiinQFo=",
+        "owner": "Kyure-A",
+        "repo": "agent-skills-nix",
+        "rev": "8326df98cf494dc515db99affa9ea9d2bd6666b6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Kyure-A",
+        "repo": "agent-skills-nix",
+        "type": "github"
+      }
+    },
+    "hallmark": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1780605762,
+        "narHash": "sha256-+yPIG1XdI6hhyOH48rd20+YlFrA9Gr416tPt1OoxfwQ=",
+        "owner": "Nutlope",
+        "repo": "hallmark",
+        "rev": "aeb42fb354ff4efa36ab475773a082315a3af2ce",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Nutlope",
+        "repo": "hallmark",
+        "type": "github"
+      }
+    },
+    "home-manager": {
+      "inputs": {
+        "nixpkgs": [
+          "agent-skills-nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1783222121,
+        "narHash": "sha256-E/ElL373TO8lQ2aMvYyzN+k4xkVaUGoRqoa8AtM71tI=",
+        "owner": "nix-community",
+        "repo": "home-manager",
+        "rev": "a1645f40777620c4bd2b6d854b290c2fc354a266",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "home-manager",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
+      "locked": {
+        "lastModified": 1783224372,
+        "narHash": "sha256-8i/87eeoqiGE4yOTjwSA3Eh/ziJRQEmd/unYU+K27sk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "d407951447dcd00442e97087bf374aad70c04cea",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1783776592,
         "narHash": "sha256-UgCQzxeWI75XM8G+hPrPh+MKzEPjG3SpAj7dtqSbksA=",
@@ -18,7 +90,9 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "agent-skills-nix": "agent-skills-nix",
+        "hallmark": "hallmark",
+        "nixpkgs": "nixpkgs_2"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index cdb4736..7f45eff 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,8 +2,13 @@
   description = "Intentional X reader";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  inputs.agent-skills-nix.url = "github:Kyure-A/agent-skills-nix";
+  inputs.hallmark = {
+    url = "github:Nutlope/hallmark";
+    flake = false;
+  };
 
-  outputs = { self, nixpkgs, ... }:
+  outputs = inputs@{ self, nixpkgs, ... }:
     let
       systems = [ "x86_64-linux" "aarch64-linux" ];
       forAllSystems = nixpkgs.lib.genAttrs systems;
@@ -55,10 +60,34 @@
         });
 
       devShells = forAllSystems (system:
-        let pkgs = import nixpkgs { inherit system; };
+        let
+          pkgs = import nixpkgs { inherit system; };
+          agentLib = inputs.agent-skills-nix.lib.agent-skills;
+          sources.hallmark = {
+            path = inputs.hallmark;
+            subdir = "skills";
+          };
+          catalog = agentLib.discoverCatalog sources;
+          allowlist = agentLib.allowlistFor {
+            inherit catalog sources;
+            enableAll = true;
+          };
+          selection = agentLib.selectSkills {
+            inherit catalog allowlist sources;
+            skills = { };
+          };
+          bundle = agentLib.mkBundle { inherit pkgs selection; };
+          localTargets = builtins.mapAttrs (_: target:
+            target // {
+              enable = true;
+            }) agentLib.defaultLocalTargets;
         in {
           default = pkgs.mkShell {
             packages = with pkgs; [ nodejs_22 pnpm chromium ];
+            shellHook = agentLib.mkShellHook {
+              inherit pkgs bundle;
+              targets = localTargets;
+            };
             PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD = "1";
             PLAYWRIGHT_CHROMIUM_EXECUTABLE =
               "${pkgs.chromium}/bin/chromium";