Model input (#6)

Optional `model` input. Defaults move to the mid tiers, `claude-sonnet-5` and `gpt-5.6-terra`, since a run follows a fixed template plus the project's checks; a workflow can still pass a bigger model.

Reviewed-on: #6
Co-authored-by: Danny Kim <temeddix@gmail.com>
Co-committed-by: Danny Kim <temeddix@gmail.com>

run.ts

@@ -20,6 +20,13 @@ const EVENT = env("EVENT_NAME");
 const AUTHOR_TOKEN = env("GITEA_TOKEN");
 const REVIEWER_TOKEN = env("REVIEWER_TOKEN");
 const RULES_PATH = "repos/commons/code-rules/raw/README.md";
+// The mid tiers: a run follows a fixed template and the project's checks.
+const DEFAULT_MODELS: Record<string, string> = {
+  claude: "claude-sonnet-5",
+  codex: "gpt-5.6-terra",
+};
+const model = (bot: string): string =>
+  Deno.env.get("MODEL") || DEFAULT_MODELS[bot];
 
 // The reviewer token is withheld so the agent cannot approve as the bot.
 const { REVIEWER_TOKEN: _, ...agentEnv } = Deno.env.toObject();
@@ -134,7 +141,7 @@ async function runClaude(prompt: string): Promise<string> {
       "--print",
       "--dangerously-skip-permissions",
       "--model",
-      "claude-fable-5",
+      model("claude"),
       "--output-format",
       "stream-json",
       "--verbose",
@@ -199,7 +206,7 @@ async function runCodex(prompt: string): Promise<string> {
     args: [
       "exec",
       "--model",
-      "gpt-5.5",
+      model("codex"),
       "--dangerously-bypass-approvals-and-sandbox",
       "--output-last-message",
       file,