diff --git a/nix/hermes-agent.nix b/nix/hermes-agent.nix
index 043d1e94202..71546c6140c 100644
--- a/nix/hermes-agent.nix
+++ b/nix/hermes-agent.nix
@@ -9,6 +9,7 @@
   stdenv,
   makeWrapper,
   callPackage,
+  python311,
   python312,
   nodejs_22,
   electron,
@@ -37,15 +38,28 @@
 }:
 let
   nodejs = nodejs_22;
+
   mkHermesVenv =
-    extraDependencyGroups:
+    {
+      extraDependencyGroups,
+      python ? null,
+    }:
     callPackage ./python.nix {
-      inherit uv2nix pyproject-nix pyproject-build-systems;
+      inherit
+        uv2nix
+        pyproject-nix
+        pyproject-build-systems
+        python
+        ;
       pythonSrc = hermesNpmLib.pythonSrc;
       dependency-groups = [ "all" ] ++ extraDependencyGroups;
     };
 
-  hermesVenv = (mkHermesVenv extraDependencyGroups).venv;
+  hermesVenv =
+    (mkHermesVenv {
+      inherit extraDependencyGroups;
+      python = python312;
+    }).venv;
 
   hermesNpmLib = callPackage ./lib.nix {
     inherit npm-lockfile-fix nodejs;
@@ -61,8 +75,7 @@ let
 
   bundledSkills = lib.cleanSourceWith {
     src = ../skills;
-    filter =
-      path: _type: !(lib.hasInfix "/index-cache/" path) && !(lib.hasInfix "/__pycache__/" path);
+    filter = path: _type: !(lib.hasInfix "/index-cache/" path) && !(lib.hasInfix "/__pycache__/" path);
   };
 
   # Optional skills are NOT in the wheel (pythonSrc excludes them, see
@@ -70,8 +83,7 @@ let
   # same mechanism Homebrew packaging uses.
   bundledOptionalSkills = lib.cleanSourceWith {
     src = ../optional-skills;
-    filter =
-      path: _type: !(lib.hasInfix "/index-cache/" path) && !(lib.hasInfix "/__pycache__/" path);
+    filter = path: _type: !(lib.hasInfix "/index-cache/" path) && !(lib.hasInfix "/__pycache__/" path);
   };
 
   # Import bundled plugins (memory, context_engine, platforms/*).  Keeping
@@ -224,8 +236,13 @@ stdenv.mkDerivation (finalAttrs: {
   '';
 
   passthru =
+    python:
     let
-      devPython = (mkHermesVenv (extraDependencyGroups ++ [ "dev" ])).editableVenv;
+      devPython =
+        (mkHermesVenv ({
+          extraDependencyGroups = extraDependencyGroups ++ [ "dev" ];
+          python = python311;
+        })).editableVenv;
     in
     {
       inherit
diff --git a/nix/python.nix b/nix/python.nix
index 602c08a3fd0..40f689736de 100644
--- a/nix/python.nix
+++ b/nix/python.nix
@@ -1,6 +1,6 @@
 # nix/python.nix — uv2nix virtual environment builder
 {
-  python312,
+  python,
   lib,
   callPackage,
   uv2nix,
@@ -65,30 +65,30 @@ let
     final: _prev:
     if isAarch64Darwin then
       {
-        numpy = mkPrebuiltOverride final python312.pkgs.numpy { };
+        numpy = mkPrebuiltOverride final python.pkgs.numpy { };
 
-        pyarrow = mkPrebuiltOverride final python312.pkgs.pyarrow { };
+        pyarrow = mkPrebuiltOverride final python.pkgs.pyarrow { };
 
-        av = mkPrebuiltOverride final python312.pkgs.av { };
+        av = mkPrebuiltOverride final python.pkgs.av { };
 
-        humanfriendly = mkPrebuiltOverride final python312.pkgs.humanfriendly { };
+        humanfriendly = mkPrebuiltOverride final python.pkgs.humanfriendly { };
 
-        coloredlogs = mkPrebuiltOverride final python312.pkgs.coloredlogs {
+        coloredlogs = mkPrebuiltOverride final python.pkgs.coloredlogs {
           humanfriendly = [ ];
         };
 
-        onnxruntime = mkPrebuiltOverride final python312.pkgs.onnxruntime {
+        onnxruntime = mkPrebuiltOverride final python.pkgs.onnxruntime {
           coloredlogs = [ ];
           numpy = [ ];
           packaging = [ ];
         };
 
-        ctranslate2 = mkPrebuiltOverride final python312.pkgs.ctranslate2 {
+        ctranslate2 = mkPrebuiltOverride final python.pkgs.ctranslate2 {
           numpy = [ ];
           pyyaml = [ ];
         };
 
-        faster-whisper = mkPrebuiltOverride final python312.pkgs.faster-whisper {
+        faster-whisper = mkPrebuiltOverride final python.pkgs.faster-whisper {
           av = [ ];
           ctranslate2 = [ ];
           huggingface-hub = [ ];
@@ -102,7 +102,7 @@ let
 
   pythonSet =
     (callPackage pyproject-nix.build.packages {
-      python = python312;
+      python = python;
     }).overrideScope
       (
         lib.composeManyExtensions [
diff --git a/notes.txt b/notes.txt
index 11abc565f39..2b80a8f5fe7 100644
--- a/notes.txt
+++ b/notes.txt
@@ -261,3 +261,52 @@ duck-typed access.
 
 all 190 are ty being unable to track either cross-module attribute init
 (186) or duck-typed hasattr-guarded access (4). no logic bugs found.
+
+### remaining 6 unresolved-attribute (post class-level annotation fix)
+
+1. **line 2162** (`object.function` ×2): duck-typed access to OpenAI SDK
+   `ChatCompletionMessageToolCall` objects. `hasattr` guard makes it safe.
+   ty can't infer the list element type through `hasattr`. not a bug.
+
+2. **lines 3586-3587** (`iteration_budget.used` / `.max_total`): `iteration_budget`
+   is `Optional[IterationBudget]` but `init_agent` always sets it to a non-None
+   value (`iteration_budget or IterationBudget(max_iterations)`). the annotation
+   says `| None` but the code guarantees non-None at runtime. not a bug — but
+   the annotation could be tightened to just `IterationBudget` (without Optional).
+
+3. **lines 4677 + 4799** (`_anthropic_client.close()`): `_anthropic_client` is
+   `Any | None` — could be None if the anthropic path was never taken. but both
+   call sites are wrapped in `try/except Exception: pass`, so even if it IS None,
+   the AttributeError is caught. safe.
+
+---
+
+## plugins/platforms/discord/adapter.py — unresolved-attribute analysis (269 errors)
+
+### root cause: ty resolving the wrong Python environment
+
+the `.venv` directory (created by `uv run` earlier) contained Python 3.13 with
+NO dependencies installed. ty auto-discovers `.venv` and uses it for module
+resolution — so it couldn't find `discord.py`, `aiohttp`, etc., producing 254
+`Module 'discord' has no member X` errors.
+
+the actual dependencies are installed in the nix develop environment
+(Python 3.12, all deps in site-packages). removing the empty `.venv` made ty
+fall back to the system/nix python, resolving all 254 import errors instantly.
+
+**fix:** `rm -rf .venv` (it was a stray artifact, not a real venv).
+also set `python-version = "3.12"` in `[tool.ty.environment]` to match the
+nix env, with a comment explaining why.
+
+**impact:** 4,422 → 3,385 diagnostics (−1,037) from this single fix.
+
+### remaining 122 discord errors (post-fix)
+
+after ty could resolve discord.py:
+- 17 `not defined on None` — `self._client` (Optional[commands.Bot]) accessed
+  before ty can prove it's non-None. all are in event handlers called after
+  the bot is ready. not bugs, but could benefit from `assert self._client is not None`
+  guards for type narrowing.
+- ~100 remaining are real type-checking errors from ty now being able to
+  see discord.py's actual types (mismatched args, wrong attribute access, etc.)
+  these need individual triage.
diff --git a/pyproject.toml b/pyproject.toml
index 93dee881279..652624f8b98 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -366,7 +366,8 @@ markers = [
 addopts = "-m 'not integration'"
 
 [tool.ty.environment]
-python-version = "3.13"
+# Match requires-python floor (>=3.11).
+python-version = "3.11"
 
 [tool.ty.rules]
 unknown-argument = "warn"