feat: add per-session model selection

src/agents/model-catalog.ts

@@ -0,0 +1,73 @@
+import { resolveClawdisAgentDir } from "./agent-paths.js";
+import { type ClawdisConfig, loadConfig } from "../config/config.js";
+import { ensureClawdisModelsJson } from "./models-config.js";
+
+export type ModelCatalogEntry = {
+  id: string;
+  name: string;
+  provider: string;
+  contextWindow?: number;
+};
+
+let modelCatalogPromise: Promise<ModelCatalogEntry[]> | null = null;
+
+export function resetModelCatalogCacheForTest() {
+  modelCatalogPromise = null;
+}
+
+export async function loadModelCatalog(params?: {
+  config?: ClawdisConfig;
+  useCache?: boolean;
+}): Promise<ModelCatalogEntry[]> {
+  if (params?.useCache === false) {
+    modelCatalogPromise = null;
+  }
+  if (modelCatalogPromise) return modelCatalogPromise;
+
+  modelCatalogPromise = (async () => {
+    const piSdk = (await import("@mariozechner/pi-coding-agent")) as {
+      discoverModels: (agentDir?: string) => Array<{
+        id: string;
+        name?: string;
+        provider: string;
+        contextWindow?: number;
+      }>;
+    };
+
+    let entries: Array<{
+      id: string;
+      name?: string;
+      provider: string;
+      contextWindow?: number;
+    }> = [];
+    try {
+      const cfg = params?.config ?? loadConfig();
+      await ensureClawdisModelsJson(cfg);
+      entries = piSdk.discoverModels(resolveClawdisAgentDir());
+    } catch {
+      entries = [];
+    }
+
+    const models: ModelCatalogEntry[] = [];
+    for (const entry of entries) {
+      const id = String(entry?.id ?? "").trim();
+      if (!id) continue;
+      const provider = String(entry?.provider ?? "").trim();
+      if (!provider) continue;
+      const name = String(entry?.name ?? id).trim() || id;
+      const contextWindow =
+        typeof entry?.contextWindow === "number" && entry.contextWindow > 0
+          ? entry.contextWindow
+          : undefined;
+      models.push({ id, name, provider, contextWindow });
+    }
+
+    return models.sort((a, b) => {
+      const p = a.provider.localeCompare(b.provider);
+      if (p !== 0) return p;
+      return a.name.localeCompare(b.name);
+    });
+  })();
+
+  return modelCatalogPromise;
+}

src/agents/model-selection.ts

@@ -0,0 +1,75 @@
+import type { ClawdisConfig } from "../config/config.js";
+import type { ModelCatalogEntry } from "./model-catalog.js";
+
+export type ModelRef = {
+  provider: string;
+  model: string;
+};
+
+export function modelKey(provider: string, model: string) {
+  return `${provider}/${model}`;
+}
+
+export function parseModelRef(
+  raw: string,
+  defaultProvider: string,
+): ModelRef | null {
+  const trimmed = raw.trim();
+  if (!trimmed) return null;
+  const slash = trimmed.indexOf("/");
+  if (slash === -1) {
+    return { provider: defaultProvider, model: trimmed };
+  }
+  const provider = trimmed.slice(0, slash).trim();
+  const model = trimmed.slice(slash + 1).trim();
+  if (!provider || !model) return null;
+  return { provider, model };
+}
+
+export function buildAllowedModelSet(params: {
+  cfg: ClawdisConfig;
+  catalog: ModelCatalogEntry[];
+  defaultProvider: string;
+}): {
+  allowAny: boolean;
+  allowedCatalog: ModelCatalogEntry[];
+  allowedKeys: Set<string>;
+} {
+  const rawAllowlist = params.cfg.agent?.allowedModels ?? [];
+  const allowAny = rawAllowlist.length === 0;
+  const catalogKeys = new Set(
+    params.catalog.map((entry) => modelKey(entry.provider, entry.id)),
+  );
+
+  if (allowAny) {
+    return {
+      allowAny: true,
+      allowedCatalog: params.catalog,
+      allowedKeys: catalogKeys,
+    };
+  }
+
+  const allowedKeys = new Set<string>();
+  for (const raw of rawAllowlist) {
+    const parsed = parseModelRef(String(raw), params.defaultProvider);
+    if (!parsed) continue;
+    const key = modelKey(parsed.provider, parsed.model);
+    if (catalogKeys.has(key)) {
+      allowedKeys.add(key);
+    }
+  }
+
+  const allowedCatalog = params.catalog.filter((entry) =>
+    allowedKeys.has(modelKey(entry.provider, entry.id)),
+  );
+
+  if (allowedCatalog.length === 0) {
+    return {
+      allowAny: true,
+      allowedCatalog: params.catalog,
+      allowedKeys: catalogKeys,
+    };
+  }
+
+  return { allowAny: false, allowedCatalog, allowedKeys };
+}