2 files changed, 29 insertions(+), 1 deletions(-)

M README.md
M modules/launcher.nix

@@ 74,6 74,7 @@ Runnable examples: [`examples/basic`](examples/basic) and
 | `packages` | Packages put on every launcher's `PATH`, e.g. tools that hooks in `claude.settings` call. |
 | `modules.skills.<name>.enable` | Declared by `mkSkillModule`; adds that skill. |
 | `launchers.<cmd>.{agent,id,stateDir}` | A command. `id` defaults to the command name; `stateDir` defaults to `~/.local/agent-environments/<id>`; it must be absolute or start with `~/`, and is taken literally. |
+| `launchers.<cmd>.sharedDirs.<dir>` | Share one directory of the state dir with another launcher, e.g. `projects = "claude-work"` for sessions and memory across logins. A managed symlink to that launcher's `<stateDir>/<dir>`, created if missing. |
 | `companions.enable` | Put every launcher of the environment on the agent's `PATH` (as companions, which cannot start companions themselves) and add a generated `companions` skill listing each one with its non-interactive call. Launchers export `AGENT_ENV_LAUNCHER` (their command name). |
 
 ## What a launcher does

@@ 41,6 41,11 @@ let
     let
       agent = build.agents.${launcher.agent};
       links = managedLinks agent;
+      # Shared directories: relative path -> shell expression for the other
+      # launcher's copy, which may live under $HOME.
+      shared = lib.mapAttrs (
+        dir: other: "${stateDirShell config.launchers.${other}.stateDir}/${lib.escapeShellArg dir}"
+      ) launcher.sharedDirs;
       runtimePath = lib.makeBinPath (
         lib.optional (companionBin != null) companionBin ++ build.runtimeInputs
       );


@@ 65,6 70,7 @@ let
         ${
           lib.concatStrings (
             lib.mapAttrsToList (p: target: "  [${lib.escapeShellArg p}]=${lib.escapeShellArg target}\n") links
+            ++ lib.mapAttrsToList (p: target: "  [${lib.escapeShellArg p}]=${target}\n") shared
           )
         })
         declare -A owned=()


@@ 92,6 98,10 @@ let
           fi
         done
 
+        # A shared directory is created where it lives, so the link never dangles.
+        ${lib.concatStrings (
+          lib.mapAttrsToList (p: _: "${mkdir} -p \"\${wanted[${lib.escapeShellArg p}]}\"\n") shared
+        )}
         for p in "''${!wanted[@]}"; do
           # No -f: a unique temp name that already exists is an error, not something to delete.
           tmp="$state/$p.agent-env-tmp.$$"


@@ 141,6 151,11 @@ in
               default = "~/.local/agent-environments/${config.id}";
               description = "State dir (CLAUDE_CONFIG_DIR / CODEX_HOME): an absolute path, or one starting with ~/ for $HOME. Taken literally.";
             };
+            sharedDirs = mkOption {
+              type = types.attrsOf types.str;
+              default = { };
+              description = "Directories of the state dir shared with another launcher: `<dir> = \"<launcher>\"` links <dir> to that launcher's <dir>, creating it if missing.";
+            };
           };
         }
       )


@@ 184,7 199,19 @@ in
           assertion = config.build.agents ? ${l.agent};
           message = "launcher '${name}' uses ${l.agent}, but ${l.agent}.enable is false";
         }
-      ]) config.launchers
+      ]
+      ++ lib.concatLists (
+        lib.mapAttrsToList (dir: other: [
+          {
+            assertion = agentEnvLib.safeName dir;
+            message = "launcher '${name}': shared dir '${dir}' is not a safe path component";
+          }
+          {
+            assertion = other != name && config.launchers ? ${other};
+            message = "launcher '${name}': shared dir '${dir}' names '${other}', which is not another launcher";
+          }
+        ]) l.sharedDirs
+      )) config.launchers
     );
   };
 }