feat: add CLI backend fallback

src/agents/cli-backends.ts

@@ -0,0 +1,110 @@
+import type { ClawdbotConfig } from "../config/config.js";
+import type { CliBackendConfig } from "../config/types.js";
+import { normalizeProviderId } from "./model-selection.js";
+
+export type ResolvedCliBackend = {
+  id: string;
+  config: CliBackendConfig;
+};
+
+const CLAUDE_MODEL_ALIASES: Record<string, string> = {
+  opus: "opus",
+  "opus-4.5": "opus",
+  "opus-4": "opus",
+  "claude-opus-4-5": "opus",
+  "claude-opus-4": "opus",
+  sonnet: "sonnet",
+  "sonnet-4.5": "sonnet",
+  "sonnet-4.1": "sonnet",
+  "sonnet-4.0": "sonnet",
+  "claude-sonnet-4-5": "sonnet",
+  "claude-sonnet-4-1": "sonnet",
+  "claude-sonnet-4-0": "sonnet",
+  haiku: "haiku",
+  "haiku-3.5": "haiku",
+  "claude-haiku-3-5": "haiku",
+};
+
+const DEFAULT_CLAUDE_BACKEND: CliBackendConfig = {
+  command: "claude",
+  args: ["-p", "--output-format", "json", "--dangerously-skip-permissions"],
+  output: "json",
+  input: "arg",
+  modelArg: "--model",
+  modelAliases: CLAUDE_MODEL_ALIASES,
+  sessionArg: "--session-id",
+  sessionMode: "always",
+  sessionIdFields: [
+    "session_id",
+    "sessionId",
+    "conversation_id",
+    "conversationId",
+  ],
+  systemPromptArg: "--append-system-prompt",
+  systemPromptMode: "append",
+  systemPromptWhen: "first",
+  clearEnv: ["ANTHROPIC_API_KEY"],
+  serialize: true,
+};
+
+function normalizeBackendKey(key: string): string {
+  return normalizeProviderId(key);
+}
+
+function pickBackendConfig(
+  config: Record<string, CliBackendConfig>,
+  normalizedId: string,
+): CliBackendConfig | undefined {
+  for (const [key, entry] of Object.entries(config)) {
+    if (normalizeBackendKey(key) === normalizedId) return entry;
+  }
+  return undefined;
+}
+
+function mergeBackendConfig(
+  base: CliBackendConfig,
+  override?: CliBackendConfig,
+): CliBackendConfig {
+  if (!override) return { ...base };
+  return {
+    ...base,
+    ...override,
+    args: override.args ?? base.args,
+    env: { ...base.env, ...override.env },
+    modelAliases: { ...base.modelAliases, ...override.modelAliases },
+    clearEnv: Array.from(
+      new Set([...(base.clearEnv ?? []), ...(override.clearEnv ?? [])]),
+    ),
+    sessionIdFields: override.sessionIdFields ?? base.sessionIdFields,
+  };
+}
+
+export function resolveCliBackendIds(cfg?: ClawdbotConfig): Set<string> {
+  const ids = new Set<string>([normalizeBackendKey("claude-cli")]);
+  const configured = cfg?.agents?.defaults?.cliBackends ?? {};
+  for (const key of Object.keys(configured)) {
+    ids.add(normalizeBackendKey(key));
+  }
+  return ids;
+}
+
+export function resolveCliBackendConfig(
+  provider: string,
+  cfg?: ClawdbotConfig,
+): ResolvedCliBackend | null {
+  const normalized = normalizeBackendKey(provider);
+  const configured = cfg?.agents?.defaults?.cliBackends ?? {};
+  const override = pickBackendConfig(configured, normalized);
+
+  if (normalized === "claude-cli") {
+    const merged = mergeBackendConfig(DEFAULT_CLAUDE_BACKEND, override);
+    const command = merged.command?.trim();
+    if (!command) return null;
+    return { id: normalized, config: { ...merged, command } };
+  }
+
+  if (!override) return null;
+  const command = override.command?.trim();
+  if (!command) return null;
+  return { id: normalized, config: { ...override, command } };
+}