diff --git a/docs/fish-config.md b/docs/fish-config.md
index 1c19733..c739c25 100644
--- a/docs/fish-config.md
+++ b/docs/fish-config.md
@@ -855,7 +855,8 @@ Add -i (interactive confirmation) to destructive commands:
                     direnv, paru/yay
       Integrations  wakatime, tailscale
       Recommended   eza, lsd, bat, btop, dust, duf, prettyping, ov,
-                    ripgrep, lazygit, lazydocker, trash, kitty, wezterm
+                    ripgrep, lazygit, lazydocker, trash, kitty, wezterm,
+                    python3
 
     fish-deps
     fish-deps install
@@ -1380,6 +1381,11 @@ fish-deps manages these tools. Run `fish-deps` to check status, or
     trash       Safe delete (trash-cli)
     kitty       GPU-accelerated terminal (primary)
     wezterm     GPU-accelerated terminal (alternative)
+    python3     Standalone interpreter — used by the AI session helpers
+                (save_claude_session / save_antigravity_session) and the
+                paru/yay log cleaner. Note: uv does not provide python3 on
+                PATH, and Arch's base does not include it, so it is listed
+                separately. All consumers degrade gracefully without it.
 
 ## Install Methods
 
diff --git a/functions/_fish_deps_catalog.fish b/functions/_fish_deps_catalog.fish
index 65f69f7..17c2946 100644
--- a/functions/_fish_deps_catalog.fish
+++ b/functions/_fish_deps_catalog.fish
@@ -16,27 +16,27 @@ function _fish_deps_catalog
     set -g _fdc_bins \
         uv cargo fish fisher starship fzf zoxide direnv paru yay \
         wakatime tailscale \
-        eza lsd bat btop dust duf prettyping ov rg lazygit lazydocker trash kitty wezterm
+        eza lsd bat btop dust duf prettyping ov rg lazygit lazydocker trash kitty wezterm python3
 
     set -g _fdc_tiers \
         req req req req req req req req rec rec \
         int int \
-        rec rec rec rec rec rec rec rec rec rec rec rec rec rec
+        rec rec rec rec rec rec rec rec rec rec rec rec rec rec rec
 
     set -g _fdc_cargo \
         "" "" "" "" starship "" zoxide "" "" "" \
         "" "" \
-        eza lsd bat "" du-dust "" "" ov ripgrep "" "" trashy "" ""
+        eza lsd bat "" du-dust "" "" ov ripgrep "" "" trashy "" "" ""
 
     set -g _fdc_pm \
         uv cargo fish "" starship fzf zoxide direnv "" yay \
         wakatime tailscale \
-        eza lsd bat btop dust duf prettyping ov ripgrep lazygit lazydocker trash kitty wezterm
+        eza lsd bat btop dust duf prettyping ov ripgrep lazygit lazydocker trash kitty wezterm python
 
     set -g _fdc_special \
         curl-uv rustup-installer git-cargo-fish fisher-bootstrap curl-installer fzf-update "" "" paru-build yay-build \
         wakatime-binary "" \
-        "" "" "" "" "" "" "" "" "" "" curl-lazydocker "" "" ""
+        "" "" "" "" "" "" "" "" "" "" curl-lazydocker "" "" "" ""
 end
 
 # SYNOPSIS
diff --git a/functions/save_antigravity_session.fish b/functions/save_antigravity_session.fish
index 6344fa6..f3e91bb 100755
--- a/functions/save_antigravity_session.fish
+++ b/functions/save_antigravity_session.fish
@@ -7,6 +7,12 @@
 set -l input (cat)
 
 # 2. Extract session_id using Python
+#    If python3 is unavailable, emit valid empty JSON and skip session
+#    tracking rather than erroring (see AGENTS.md Convention §6).
+if not type -q python3
+    echo '{}'
+    exit 0
+end
 set -l sid (echo $input | python3 -c "import sys,json; print(json.load(sys.stdin).get('session_id', ''))")
 set -l session_file ".antigravity_session"
 
diff --git a/functions/save_claude_session.fish b/functions/save_claude_session.fish
index eef53ed..bdbb520 100755
--- a/functions/save_claude_session.fish
+++ b/functions/save_claude_session.fish
@@ -4,7 +4,14 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
 # 1. Read input and extract session ID
+#    python3 parses the session_id out of the hook's JSON payload. If it is
+#    unavailable we emit valid empty JSON and skip session tracking rather
+#    than erroring (see AGENTS.md Convention §6).
 set -l input (cat)
+if not type -q python3
+    echo '{}'
+    exit 0
+end
 set -l sid (echo $input | python3 -c "import sys,json; print(json.load(sys.stdin).get('session_id', ''))")
 set -l session_file ".claude_session"