diff --git a/packages/provider-pi/src/server/adapter.test.ts b/packages/provider-pi/src/server/adapter.test.ts
index 06ad17f0568b..21ea842b917e 100644
--- a/packages/provider-pi/src/server/adapter.test.ts
+++ b/packages/provider-pi/src/server/adapter.test.ts
@@ -2274,6 +2274,59 @@ describe("PiAdapterV2", () => {
     }).pipe(Effect.scoped, Effect.provide(layerTest)),
   );
 
+  it.effect("selects the provider and id Pi reported when either contains a slash", () =>
+    Effect.gen(function* () {
+      const fake = yield* makeFakePi;
+      const hub = "hub=https://hub.example:8318/v1";
+      fake.queueModels([{ provider: "openrouter", id: "openrouter/auto" }]);
+      const { runtime, takeEvent } = yield* openRuntime(fake);
+      const providerThread = yield* runtime.ensureThread({
+        threadId: THREAD_ID,
+        modelSelection: modelSelection("default"),
+        runtimePolicy,
+      });
+
+      yield* startTurn(
+        runtime,
+        providerThread,
+        "default",
+        [],
+        "First",
+        modelSelection("openrouter/openrouter/auto"),
+      );
+      const openRouterRequest = yield* fake.takeRequest("set_model");
+      assert.deepEqual(
+        { provider: openRouterRequest["provider"], modelId: openRouterRequest["modelId"] },
+        { provider: "openrouter", modelId: "openrouter/auto" },
+      );
+      yield* fake.takeRequest("prompt");
+      yield* fake.emit({ type: "agent_start" });
+      yield* fake.emit({ type: "agent_end", messages: [], willRetry: false });
+      yield* fake.emit({ type: "agent_settled" });
+      yield* takeEvent((event) => event.type === "turn.terminal");
+
+      // A provider registered after the session started, e.g. by an extension reload.
+      fake.queueModels([
+        { provider: "openrouter", id: "openrouter/auto" },
+        { provider: hub, id: "claude-haiku-4-5" },
+      ]);
+      yield* startTurn(
+        runtime,
+        providerThread,
+        "default",
+        [],
+        "Second",
+        modelSelection(`${hub}/claude-haiku-4-5`),
+        2,
+      );
+      const hubRequest = yield* fake.takeRequest("set_model");
+      assert.deepEqual(
+        { provider: hubRequest["provider"], modelId: hubRequest["modelId"] },
+        { provider: hub, modelId: "claude-haiku-4-5" },
+      );
+    }).pipe(Effect.scoped, Effect.provide(layerTest)),
+  );
+
   it.effect.each(["anthropic/model-b", "default"])(
     "preserves explicit thinking when switching models to %s in the same runtime",
     (targetModel) =>
diff --git a/packages/provider-pi/src/server/adapter.ts b/packages/provider-pi/src/server/adapter.ts
index a82a7f45f4e4..90c262b28108 100644
--- a/packages/provider-pi/src/server/adapter.ts
+++ b/packages/provider-pi/src/server/adapter.ts
@@ -58,8 +58,9 @@ import {
 } from "@t3tools/provider-core/server/failure";
 import { turnScopedSelectionTransition } from "@t3tools/provider-core/server/selectionTransition";
 import {
+  findReportedPiModel,
   makePiRpcConnection,
-  parsePiModelSlug,
+  resolvePiModelSlug,
   piRecordField as recordField,
   piRecordNumber as recordNumber,
   piRecordString as recordString,
@@ -589,7 +590,7 @@ export const makePiAdapterV2 = Effect.fn("makePiAdapterV2")(function* (
       let baselineThinking: string | null = null;
       let contextWindow: number | null = null;
       const modelContextWindows = new Map<string, number>();
-      let modelsDiscovered = false;
+      let discoveredModels: ReadonlyArray<unknown> | null = null;
       // Prompt ACKs lack IDs; retain session send order and ownership so late ACKs cannot affect new turns.
       const pendingPromptResponses: Array<PiPromptSend> = [];
       const pendingCompactResponses: Array<{
@@ -2420,6 +2421,17 @@ export const makePiAdapterV2 = Effect.fn("makePiAdapterV2")(function* (
         Effect.forkIn(scope),
       );
 
+      const discoverModels = Effect.fnUntraced(function* () {
+        const modelsData = yield* request({ type: "get_available_models" }).pipe(
+          Effect.orElseSucceed(() => undefined),
+        );
+        const models = recordField(modelsData, "models");
+        if (Array.isArray(models)) {
+          for (const model of models) rememberModelContextWindow(model);
+          discoveredModels = models;
+        }
+      });
+
       const registerThread = Effect.fnUntraced(function* (
         threadInput: ProviderAdapter.ProviderAdapterV2EnsureThreadInput,
         publish = true,
@@ -2468,16 +2480,7 @@ export const makePiAdapterV2 = Effect.fn("makePiAdapterV2")(function* (
           }
         }
         const stateData = yield* request({ type: "get_state" });
-        if (!modelsDiscovered) {
-          const modelsData = yield* request({ type: "get_available_models" }).pipe(
-            Effect.orElseSucceed(() => undefined),
-          );
-          const models = recordField(modelsData, "models");
-          if (Array.isArray(models)) {
-            for (const model of models) rememberModelContextWindow(model);
-            modelsDiscovered = true;
-          }
-        }
+        if (discoveredModels === null) yield* discoverModels();
         contextWindow = rememberModelContextWindow(recordField(stateData, "model"));
         // Capture each baseline before applying selections so our own choices cannot become Pi defaults.
         if (baselineModel === null && appliedModel === null) {
@@ -2573,7 +2576,11 @@ export const makePiAdapterV2 = Effect.fn("makePiAdapterV2")(function* (
             appliedThinking = baselineThinking;
           }
         } else if (modelSelection.model !== appliedModel) {
-          const parsed = parsePiModelSlug(modelSelection.model);
+          // Extensions and models.json edits can add providers after the first discovery.
+          if (findReportedPiModel(modelSelection.model, discoveredModels) === undefined) {
+            yield* discoverModels();
+          }
+          const parsed = resolvePiModelSlug(modelSelection.model, discoveredModels);
           if (parsed === null) {
             return yield* protocolError(
               `Pi model '${modelSelection.model}' must use provider/model format`,
diff --git a/packages/provider-pi/src/server/rpc.ts b/packages/provider-pi/src/server/rpc.ts
index 98eacd790139..9b016051a150 100644
--- a/packages/provider-pi/src/server/rpc.ts
+++ b/packages/provider-pi/src/server/rpc.ts
@@ -58,7 +58,28 @@ export function piRecordNumber(input: unknown, key: string): number | undefined
   return Predicate.isNumber(value) && Number.isFinite(value) ? value : undefined;
 }
 
-export function parsePiModelSlug(slug: string): { provider: string; modelId: string } | null {
+// Pi provider names and model ids may both contain "/", so a slug only splits
+// reliably through the `{provider, id}` pairs `get_available_models` reported.
+export function findReportedPiModel(
+  slug: string,
+  reportedModels: unknown,
+): { provider: string; modelId: string } | undefined {
+  if (!Array.isArray(reportedModels)) return undefined;
+  for (const model of reportedModels) {
+    const provider = piRecordString(model, "provider");
+    const modelId = piRecordString(model, "id");
+    if (provider !== undefined && modelId !== undefined && `${provider}/${modelId}` === slug)
+      return { provider, modelId };
+  }
+  return undefined;
+}
+
+export function resolvePiModelSlug(
+  slug: string,
+  reportedModels: unknown,
+): { provider: string; modelId: string } | null {
+  const reported = findReportedPiModel(slug, reportedModels);
+  if (reported !== undefined) return reported;
   const separator = slug.indexOf("/");
   if (separator <= 0 || separator === slug.length - 1) return null;
   return { provider: slug.slice(0, separator), modelId: slug.slice(separator + 1) };
diff --git a/packages/provider-pi/src/server/textGeneration.test.ts b/packages/provider-pi/src/server/textGeneration.test.ts
index 0e6a8a3c0778..eda86cd2e62a 100644
--- a/packages/provider-pi/src/server/textGeneration.test.ts
+++ b/packages/provider-pi/src/server/textGeneration.test.ts
@@ -19,6 +19,7 @@ const makeFakePi = (
   reply: string,
   setModelError?: string,
   turnEvents: ReadonlyArray<Record<string, unknown>> = [],
+  models?: ReadonlyArray<Record<string, unknown>>,
 ) =>
   Effect.gen(function* () {
     const stdout = yield* Queue.unbounded<Uint8Array, Cause.Done>();
@@ -41,6 +42,8 @@ const makeFakePi = (
             yield* emit({ type: "agent_settled" });
           } else if (record["type"] === "get_last_assistant_text") {
             yield* emit({ ...response, success: true, data: { text: reply } });
+          } else if (record["type"] === "get_available_models" && models !== undefined) {
+            yield* emit({ ...response, success: true, data: { models } });
           } else if (record["type"] === "set_model" && setModelError !== undefined) {
             yield* emit({ ...response, success: false, error: setModelError });
           } else {
@@ -124,6 +127,36 @@ it.effect("names the model and the disabled extensions when Pi cannot load it",
   }),
 );
 
+it.effect("selects the provider and id Pi reported when the provider contains a slash", () =>
+  Effect.gen(function* () {
+    const provider = "llama-server=http://127.0.0.1:8080";
+    const pi = yield* makeFakePi(
+      JSON.stringify({ subject: "Update README", body: "" }),
+      undefined,
+      [],
+      [{ provider, id: "qwen3" }],
+    );
+    const textGeneration = yield* makePiTextGeneration(
+      { enabled: true, binaryPath: "pi", launchArgs: "", customModels: [] },
+      {},
+    ).pipe(Effect.provideService(ChildProcessSpawner.ChildProcessSpawner, pi.spawner));
+
+    yield* textGeneration.generateCommitMessage({
+      cwd: process.cwd(),
+      branch: "main",
+      stagedSummary: "M README.md",
+      stagedPatch: "diff --git a/README.md b/README.md",
+      modelSelection: createModelSelection(ProviderInstanceId.make("pi"), `${provider}/qwen3`),
+    });
+
+    const setModel = pi.received.find((record) => record["type"] === "set_model");
+    assert.deepEqual(
+      { provider: setModel?.["provider"], modelId: setModel?.["modelId"] },
+      { provider, modelId: "qwen3" },
+    );
+  }),
+);
+
 const failedTurnWith = (errorMessage: string) => ({
   type: "message_end",
   message: { role: "assistant", stopReason: "error", errorMessage },
diff --git a/packages/provider-pi/src/server/textGeneration.ts b/packages/provider-pi/src/server/textGeneration.ts
index 40697f2d4280..8b75b3c3c0ba 100644
--- a/packages/provider-pi/src/server/textGeneration.ts
+++ b/packages/provider-pi/src/server/textGeneration.ts
@@ -7,7 +7,7 @@ import * as ChildProcessSpawner from "effect/process/ChildProcessSpawner";
 import { TextGenerationError } from "@t3tools/contracts";
 import type { PiSettings } from "../settings.ts";
 
-import { makePiRpcConnection, parsePiModelSlug, piRecordString } from "./rpc.ts";
+import { makePiRpcConnection, piRecordField, piRecordString, resolvePiModelSlug } from "./rpc.ts";
 import { buildPiRpcLaunch, resolvePiLaunchArgs } from "./mcpInjection.ts";
 import * as TextGenerationOperations from "@t3tools/provider-core/server/textGenerationOperations";
 
@@ -61,7 +61,10 @@ export const makePiTextGeneration = Effect.fn("makePiTextGeneration")(function*
 
       if (modelSelection.model !== "default") {
         // Reject unusable custom slugs; silently using Pi's default would misreport the requested model.
-        const parsed = parsePiModelSlug(modelSelection.model);
+        const inventory = yield* connection
+          .request({ type: "get_available_models" })
+          .pipe(Effect.orElseSucceed(() => undefined));
+        const parsed = resolvePiModelSlug(modelSelection.model, piRecordField(inventory, "models"));
         if (parsed === null) {
           return yield* new TextGenerationError({
             operation,