diff --git a/packages/cli/src/doctor.mjs b/packages/cli/src/doctor.mjs
index 891e7e41..4287f6d6 100644
--- a/packages/cli/src/doctor.mjs
+++ b/packages/cli/src/doctor.mjs
@@ -53,17 +53,72 @@ function checkAgent(dir, name) {
   const path = join(dir, relative);
   if (!existsSync(path)) return failed(relative, "missing");
   const source = readFileSync(path, "utf8").replace(/\r\n?/g, "\n");
-  if (!source.startsWith("---\n") || !/\n---\n[\s\S]*\S/.test(source)) return failed(relative, "invalid frontmatter or empty prompt");
-  if (!new RegExp(`^name:\\s*${escapeRegExp(name)}\\s*$`, "m").test(source)) return failed(relative, `name must be ${name}`);
-  if (!/^engine:\s*(?:claude_code|codex)\s*$/m.test(source)) return failed(relative, "engine must be claude_code or codex");
-  if (!/^model:\s*\S+\s*$/m.test(source)) return failed(relative, "model is missing");
-  if (!/^triggers:\s*$/m.test(source) || !/^\s{2}- type:\s*(?:manual|schedule|github)\s*$/m.test(source)) {
+  const parsed = splitFrontmatter(source);
+  if (!parsed || !parsed.prompt.trim()) return failed(relative, "invalid frontmatter or empty prompt");
+  const { frontmatter } = parsed;
+  if (!new RegExp(`^name:\\s*${escapeRegExp(name)}\\s*$`, "m").test(frontmatter)) {
+    return failed(relative, `name must be ${name}`);
+  }
+  if (!/^engine:\s*(?:claude_code|codex)\s*$/m.test(frontmatter)) {
+    return failed(relative, "engine must be claude_code or codex");
+  }
+  if (!agentModel(frontmatter)) return failed(relative, "model is missing or invalid");
+  if (
+    !/^triggers:\s*$/m.test(frontmatter) ||
+    !/^\s{2}- type:\s*(?:manual|schedule|github|mcp|ui)\s*$/m.test(frontmatter)
+  ) {
     return failed(relative, "at least one supported trigger is required");
   }
-  if (/^(?:permissions|sandbox|tools):/m.test(source)) return failed(relative, "per-agent access controls are not supported");
+  if (/^(?:permissions|sandbox|tools):/m.test(frontmatter)) {
+    return failed(relative, "per-agent access controls are not supported");
+  }
   return passed(relative, "valid agent manifest");
 }
 
+function splitFrontmatter(source) {
+  const match = /^---\n([\s\S]*?)\n---(?:\n|$)([\s\S]*)$/.exec(source);
+  if (!match) return null;
+  return { frontmatter: match[1] ?? "", prompt: match[2] ?? "" };
+}
+
+const MODEL_MAX = 160;
+
+function agentModel(frontmatter) {
+  const match = /^model:\s*(.*)$/m.exec(frontmatter);
+  if (!match) return null;
+  const value = yamlStringScalar(match[1]);
+  if (value === null || value.length < 1 || value.length > MODEL_MAX) return null;
+  return value;
+}
+
+function yamlStringScalar(raw) {
+  const source = raw.trim();
+  if (!source || source.startsWith("#")) return null;
+  if (source.startsWith('"')) return yamlDoubleQuoted(source);
+  if (source.startsWith("'")) return yamlSingleQuoted(source);
+  if (source.startsWith("|") || source.startsWith(">")) return null;
+  const comment = /[\t ]#/.exec(source);
+  const plain = (comment ? source.slice(0, comment.index) : source).trim();
+  return plain || null;
+}
+
+function yamlDoubleQuoted(source) {
+  const match = /^("(?:\\.|[^"\\\n])*")\s*(?:#.*)?$/.exec(source);
+  if (!match) return null;
+  try {
+    const parsed = JSON.parse(match[1]);
+    return typeof parsed === "string" ? parsed : null;
+  } catch {
+    return null;
+  }
+}
+
+function yamlSingleQuoted(source) {
+  const match = /^('(?:[^']|'')*')\s*(?:#.*)?$/.exec(source);
+  if (!match) return null;
+  return match[1].slice(1, -1).replaceAll("''", "'");
+}
+
 function passed(label, detail) {
   return { label, ok: true, detail };
 }
diff --git a/packages/cli/test/init.test.mjs b/packages/cli/test/init.test.mjs
index 8fc2c656..43916ac6 100644
--- a/packages/cli/test/init.test.mjs
+++ b/packages/cli/test/init.test.mjs
@@ -198,6 +198,79 @@ test("local doctor validates the 0.12 contract and preserves its JSON output", (
   assert.match(invalidPort.stdout, /between 1 and 65535/);
 });
 
+test("doctor inspects agent frontmatter only and accepts quoted models and mcp/ui triggers", (t) => {
+  const dir = makeTargetRepo();
+  t.after(() => rmSync(dir, { recursive: true, force: true }));
+  const init = runCli(
+    ["init", "--yes", `--dir=${dir}`, "--repo=acme/demo-app", "--start=npm run dev"],
+    dir,
+  );
+  assert.equal(init.status, 0, init.stdout + init.stderr);
+
+  const builderPath = join(dir, ".agents/builder.md");
+  const original = readFileSync(builderPath, "utf8");
+
+  writeFileSync(
+    builderPath,
+    `${original.trimEnd()}\n\npermissions:\n  contents: read\n`,
+  );
+  const promptPermissions = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(promptPermissions.status, 0, promptPermissions.stdout + promptPermissions.stderr);
+
+  writeFileSync(
+    builderPath,
+    original.replace(/^name: builder$/m, "name: not-builder") + "\nname: builder\n",
+  );
+  const hiddenName = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(hiddenName.status, 1);
+  assert.match(hiddenName.stdout, /name must be builder/);
+
+  writeFileSync(
+    builderPath,
+    original.replace(/^model: .+$/m, 'model: "gpt-5.6-sol with spaces"'),
+  );
+  const quotedModel = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(quotedModel.status, 0, quotedModel.stdout + quotedModel.stderr);
+
+  writeFileSync(builderPath, original.replace(/^model: .+$/m, "model: # choose a model"));
+  const commentModel = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(commentModel.status, 1);
+  assert.match(commentModel.stdout, /model is missing or invalid/);
+
+  writeFileSync(builderPath, original.replace(/^model: .+$/m, 'model: "unclosed'));
+  const unclosedModel = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(unclosedModel.status, 1);
+  assert.match(unclosedModel.stdout, /model is missing or invalid/);
+
+  writeFileSync(
+    builderPath,
+    [
+      "---",
+      "name: builder",
+      "description: Implements a complete story.",
+      "engine: codex",
+      "model: gpt-5.6-sol",
+      "enabled: true",
+      "triggers:",
+      "  - type: mcp",
+      "  - type: ui",
+      "---",
+      "",
+      "# Builder",
+      "",
+      "Complete the story.",
+      "",
+    ].join("\n"),
+  );
+  const interactiveOnly = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(interactiveOnly.status, 0, interactiveOnly.stdout + interactiveOnly.stderr);
+
+  writeFileSync(builderPath, original.replace(/^enabled: true$/m, "permissions: {}\nenabled: true"));
+  const frontmatterPermissions = runCli(["doctor", `--dir=${dir}`, "--json"], dir);
+  assert.equal(frontmatterPermissions.status, 1);
+  assert.match(frontmatterPermissions.stdout, /per-agent access controls are not supported/);
+});
+
 test("local commands reject unknown and valueless flags and legacy commands", () => {
   const unknown = runCli(["doctor", "--jsoon"]);
   assert.equal(unknown.status, 1);