fix(deps): use host-provided pi core packages

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+
+- Use the host-provided `pi-ai` and `pi-coding-agent` core packages instead of installing a private pinned `pi-ai` runtime copy.
+
 ## 0.4.4 - 2026-08-03
 
 - Fix cached input tokens being counted twice.

package.json

@@ -49,18 +49,20 @@
     ]
   },
   "devDependencies": {
+    "@earendil-works/pi-ai": "*",
     "@types/node": "25.6.0",
     "prettier": "^3.5.0",
     "tsx": "4.22.4",
     "typescript": "6.0.3"
   },
-  "dependencies": {
-    "@earendil-works/pi-ai": "0.75.5"
-  },
   "peerDependencies": {
-    "@earendil-works/pi-coding-agent": "^0.75.5"
+    "@earendil-works/pi-ai": "*",
+    "@earendil-works/pi-coding-agent": "*"
   },
   "peerDependenciesMeta": {
+    "@earendil-works/pi-ai": {
+      "optional": true
+    },
     "@earendil-works/pi-coding-agent": {
       "optional": true
     }

src/cost.ts

@@ -13,7 +13,7 @@ export function calculateCommandCodeCost(model: ModelLike, usage: Usage): void {
   usage.cost.input = (model.cost.input / 1_000_000) * usage.input
   usage.cost.output = (model.cost.output / 1_000_000) * usage.output
   usage.cost.cacheRead = (model.cost.cacheRead / 1_000_000) * usage.cacheRead
-  usage.cost.cacheWrite = (model.cost.cacheWrite / 1_000_000) * usage.cacheWrite
+  usage.cost.cacheWrite = (model.cost.cacheWrite * usage.cacheWrite) / 1_000_000
   usage.cost.total =
     usage.cost.input + usage.cost.output + usage.cost.cacheRead + usage.cost.cacheWrite
 }