fix(tui): add /install openspec and stop ANTHROPIC_API_KEY hijacking claude sessions

- /install openspec (and /install spec) installs @fission-ai/openspec via npm
  global; idempotent, with a live install marker on the /spec help line.
- openSession scrubs ANTHROPIC_API_KEY/ANTHROPIC_AUTH_TOKEN + nested-session
  markers for the claude engine only, so passthrough sessions use Claude Code's
  own stored login instead of an inherited key that triggers the "enable models"
  screen and exits. opencode/aider keep the key (they use it as a provider key).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ralyodio

src/engines.mjs

@@ -16,6 +16,17 @@ export const ENGINES = {
     desc: "Claude Code — Anthropic's agentic CLI",
     bin: "claude",
     install: { cmd: "npm", args: ["install", "-g", "@anthropic-ai/claude-code"] },
+    // Claude Code authenticates via its own stored login (~/.claude). An
+    // inherited ANTHROPIC_API_KEY hijacks that subscription auth — and if the
+    // key can't serve the models, Claude Code shows an "enable models" screen
+    // and exits straight back to the mosh prompt. Nested-session markers make a
+    // fresh launch think it's running inside another Claude. Drop both so the
+    // passthrough session starts clean on its own auth. (opencode/aider legitimately
+    // use ANTHROPIC_API_KEY as a provider key, so we only scrub it for claude.)
+    stripEnv: [
+      "ANTHROPIC_API_KEY", "ANTHROPIC_AUTH_TOKEN",
+      "CLAUDECODE", "CLAUDE_CODE_ENTRYPOINT", "CLAUDE_CODE_SESSION_ID", "CLAUDE_CODE_CHILD_SESSION",
+    ],
   },
   codex: {
     desc: "Codex — OpenAI's coding CLI",
@@ -72,8 +83,13 @@ export function engineList() {
  */
 export function openSession(engine, args = []) {
   return new Promise((resolve) => {
+    let env = process.env;
+    if (engine.stripEnv?.length) {
+      env = { ...process.env };
+      for (const k of engine.stripEnv) delete env[k];
+    }
     let child;
-    try { child = spawn(engine.bin, args, { stdio: "inherit" }); }
+    try { child = spawn(engine.bin, args, { stdio: "inherit", env }); }
     catch (e) { resolve({ ok: false, error: e }); return; }
     child.on("error", (e) => resolve({ ok: false, error: e }));
     child.on("exit", (code, signal) => resolve({ ok: true, code, signal }));

src/spec.mjs

@@ -7,6 +7,8 @@
 import { spawn } from "node:child_process";
 import { isInstalled } from "./engines.mjs";
 
+export { isInstalled };
+
 export const OPENSPEC = {
   pkg: "@fission-ai/openspec",
   bin: "openspec",
@@ -25,6 +27,26 @@ export function resolveSpec(args = []) {
   return { cmd: "npx", args: ["-y", `${OPENSPEC.pkg}@latest`, ...args], viaNpx: true };
 }
 
+/** True when the `openspec` binary is resolvable on PATH. */
+export function isSpecInstalled() {
+  return isInstalled(OPENSPEC.bin);
+}
+
+/**
+ * Install the OpenSpec CLI globally (same deal as engines — we drive it, don't
+ * vendor it). stdio inherited so npm's own progress owns the terminal. Resolves
+ * { ok, code } | { ok:false, error }.
+ */
+export function installSpec() {
+  return new Promise((resolve) => {
+    let child;
+    try { child = spawn(OPENSPEC.install.cmd, OPENSPEC.install.args, { stdio: "inherit" }); }
+    catch (e) { resolve({ ok: false, error: e }); return; }
+    child.on("error", (e) => resolve({ ok: false, error: e }));
+    child.on("exit", (code) => resolve({ ok: true, code }));
+  });
+}
+
 /**
  * Run openspec with stdio inherited so it fully owns the terminal (its own
  * prompts/output — full passthrough). Resolves { ok, code, viaNpx }.

src/tui.mjs

@@ -8,7 +8,7 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import { ENGINES, resolveEngine, engineStatus, openSession } from "./engines.mjs";
-import { runSpec } from "./spec.mjs";
+import { runSpec, installSpec, isSpecInstalled, OPENSPEC } from "./spec.mjs";
 import { compile, run } from "./interpreter.mjs";
 import { defaultCommands } from "./commands.mjs";
 import { banner, hr, acid, ash, bone, dim, ok, err, info } from "./ui.mjs";
@@ -68,8 +68,9 @@ function printHelp() {
     bone("  commands"),
     `   ${acid("/agents")}            list coding engines`,
     `   ${acid("/agents <name>")}     open a session (claude · codex · gemini · aider · opencode)`,
-    `   ${acid("/install <name>")}    install an engine`,
-    `   ${acid("/spec [init|…]")}     spec-driven dev — writes openspec/ to your repo (OpenSpec)`,
+    `   ${acid("/install <name>")}    install an engine (or ${bone("openspec")})`,
+    `   ${acid("/spec [init|…]")}     spec-driven dev — writes openspec/ to your repo (OpenSpec)` +
+      ash(isSpecInstalled() ? "  ●" : "  ○ /install openspec"),
     `   ${acid("/run <file.mosh>")}   run a moshscript program`,
     `   ${acid("/help")}              this`,
     `   ${acid("/quit")}              leave the pit  (or Ctrl-D)`,
@@ -107,6 +108,16 @@ function installEngine(key) {
   });
 }
 
+async function installOpenSpec() {
+  if (isSpecInstalled()) { console.log(ok("openspec already installed. 🤘  try /spec init")); return; }
+  console.log(info(`installing openspec: ${OPENSPEC.install.cmd} ${OPENSPEC.install.args.join(" ")}`));
+  console.log(hr());
+  const r = await installSpec();
+  console.log(hr());
+  if (!r.ok) { console.log(err(`install failed: ${r.error?.message || r.error}`)); return; }
+  console.log(r.code === 0 ? ok("openspec installed. 🤘  try /spec init") : err(`install exited ${r.code}`));
+}
+
 async function openSpec(args) {
   console.log(info(`openspec — spec-driven dev, saved to ${bone("openspec/")} in your repo. hand-off to its CLI…`));
   console.log(hr());
@@ -160,9 +171,11 @@ export async function tui() {
       continue;
     }
     if (cmd === "install") {
-      if (!rest[0]) { console.log(err("usage: /install <engine>")); continue; }
+      if (!rest[0]) { console.log(err("usage: /install <engine|openspec>")); continue; }
+      const target = rest[0].toLowerCase();
       rl.close();
-      await installEngine(rest[0].toLowerCase());
+      if (target === "openspec" || target === "spec") await installOpenSpec();
+      else await installEngine(target);
       rl = mkrl();
       continue;
     }