diff --git a/README.md b/README.md
index 156b31f..cdb99b2 100644
--- a/README.md
+++ b/README.md
@@ -78,6 +78,15 @@ OLLIE_MEMORY_PATH=~/.config/ollie/memory  # directory for memory files (ollie/m)
 OLLIE_ELEVATE_SOCKET=${XDG_RUNTIME_DIR}/ollie/elevate.sock  # socket path for x/elevate adapter (default: $XDG_RUNTIME_DIR/ollie/elevate.sock)
 OLLIE_COMPLETE_BACKEND=ollama             # backend for u/complete (required)
 OLLIE_COMPLETE_MODEL=qwen3:latest         # model for u/complete (required)
+OLLIE_ENABLED_BACKENDS=openrouter,anthropic  # backends available for routing (comma-separated)
+
+# Per-backend tier models for t/route
+OLLIE_TIER_WORKER_openrouter=mistralai/devstral-small
+OLLIE_TIER_EXPERT_openrouter=anthropic/claude-sonnet-4-20250514
+OLLIE_TIER_WORKER_anthropic=claude-haiku-4-20250514
+OLLIE_TIER_EXPERT_anthropic=claude-sonnet-4-20250514
+OLLIE_TIER_WORKER_ollama=qwen3:8b
+OLLIE_TIER_EXPERT_ollama=qwen3:32b
 ```
 
 Shell environment variables take precedence over the env file.
diff --git a/prompts/tools-route.md b/prompts/tools-route.md
index 3d8c802..27a21b1 100644
--- a/prompts/tools-route.md
+++ b/prompts/tools-route.md
@@ -6,11 +6,14 @@ Route a subtask to an appropriate model tier. Fire-and-forget: returns immediate
 - `worker` (default) — scoped tasks: implement a function, apply an edit, investigate a file, extract information.
 - `expert` — tasks requiring deep reasoning, architectural judgment, or multi-file analysis with ambiguity.
 
+Available backends for routing are listed in `$OLLIE_ENABLED_BACKENDS` (comma-separated).
+
 **Calling convention**:
 ```
 call_tool: calls=[{tool: "route", args: ["<instruction>"]}]
 call_tool: calls=[{tool: "route", args: ["<instruction>", "--tier=worker"]}]
 call_tool: calls=[{tool: "route", args: ["<instruction>", "--tier=expert"]}]
+call_tool: calls=[{tool: "route", args: ["<instruction>", "--tier=expert", "--backend=anthropic"]}]
 ```
 
 Parallel fan-out:
@@ -35,3 +38,4 @@ SUMMARY: <result>
 - Never wait for results. Continue work or end your turn.
 - One task per call.
 - Default to `worker`. Use `expert` only when the task genuinely needs stronger reasoning.
+- `--backend` overrides the default (parent's backend). Use when a specific backend is better suited.
diff --git a/tools/route b/tools/route
index 207208c..94666b9 100755
--- a/tools/route
+++ b/tools/route
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # ollie:parallel read
 # description: Route a subtask to an appropriate model tier. Returns immediately; the agent reports back to your prompt when done.
-# Args: <instruction> [--tier=worker|expert] [id]
+# Args: <instruction> [--tier=worker|expert] [--backend=<name>] [id]
 set -euo pipefail
 
 OLLIE="${OLLIE:-$HOME/mnt/ollie}"
@@ -12,11 +12,13 @@ die() { printf 'route: %s\n' "$*" >&2; exit 1; }
 
 # Parse args
 tier="worker"
+backend_override=""
 instruction=""
 id=""
 for arg in "$@"; do
     case "$arg" in
         --tier=*) tier="${arg#--tier=}" ;;
+        --backend=*) backend_override="${arg#--backend=}" ;;
         *) [ -z "$instruction" ] && instruction="$arg" || id="$arg" ;;
     esac
 done
@@ -24,19 +26,37 @@ done
 [ -z "$instruction" ] && die "instruction required"
 
 case "$tier" in
-    worker)
-        BACKEND="${OLLIE_CASCADE_BACKEND:-openrouter}"
-        MODEL="${OLLIE_CASCADE_MODEL:-mistralai/devstral-small}"
-        agent="worker"
-        ;;
-    expert)
-        BACKEND="${OLLIE_ESCALATE_BACKEND:-openrouter}"
-        MODEL="${OLLIE_ESCALATE_MODEL:-anthropic/claude-sonnet-4-20250514}"
-        agent="expert"
-        ;;
+    worker|expert) ;;
     *) die "unknown tier: $tier (use worker or expert)" ;;
 esac
 
+# Resolve backend: explicit flag > parent session's backend > OLLIE_BACKEND
+if [ -n "$backend_override" ]; then
+    BACKEND="$backend_override"
+else
+    BACKEND=$(cat "$OLLIE/s/$OLLIE_SESSION_ID/backend" 2>/dev/null || echo "${OLLIE_BACKEND:-openrouter}")
+fi
+
+# Resolve model: OLLIE_TIER_{TIER}_{BACKEND} > legacy flat vars > hardcoded defaults
+tier_upper=$(echo "$tier" | tr '[:lower:]' '[:upper:]')
+backend_lower=$(echo "$BACKEND" | tr '[:upper:]' '[:lower:]')
+tier_var="OLLIE_TIER_${tier_upper}_${backend_lower}"
+MODEL="${!tier_var:-}"
+
+if [ -z "$MODEL" ]; then
+    # Legacy fallback
+    case "$tier" in
+        worker) MODEL="${OLLIE_CASCADE_MODEL:-mistralai/devstral-small}" ;;
+        expert) MODEL="${OLLIE_ESCALATE_MODEL:-anthropic/claude-sonnet-4-20250514}" ;;
+    esac
+fi
+
+# Agent config
+case "$tier" in
+    worker) agent="worker" ;;
+    expert) agent="expert" ;;
+esac
+
 id="${id:-route-${tier}-$(date +%s%N)-$$}"
 [ -n "$OLLIE_SESSION_ID" ] && id="${OLLIE_SESSION_ID}__${id}"