diff --git a/bin/cli/commands/chat.mjs b/bin/cli/commands/chat.mjs
new file mode 100644
index 0000000000..f5d6ba6006
--- /dev/null
+++ b/bin/cli/commands/chat.mjs
@@ -0,0 +1,162 @@
+import { appendFileSync, readFileSync } from "node:fs";
+import { join } from "node:path";
+import { apiFetch } from "../api.mjs";
+import { emit } from "../output.mjs";
+import { t } from "../i18n.mjs";
+import { resolveDataDir } from "../data-dir.mjs";
+
+function resolveHistoryPath() {
+  return join(resolveDataDir(), "cli-history.jsonl");
+}
+
+export function registerChat(program) {
+  program
+    .command("chat [prompt]")
+    .description(t("chat.description"))
+    .option("--file <path>", t("chat.file"))
+    .option("--stdin", t("chat.stdin"))
+    .option("-s, --system <prompt>", t("chat.system"))
+    .option("-m, --model <id>", t("chat.model"), "auto")
+    .option("--max-tokens <n>", t("chat.max_tokens"), parseInt)
+    .option("--temperature <t>", t("chat.temperature"), parseFloat)
+    .option("--top-p <p>", t("chat.top_p"), parseFloat)
+    .option("--reasoning-effort <level>", t("chat.reasoning_effort"))
+    .option("--thinking-budget <tokens>", t("chat.thinking_budget"), parseInt)
+    .option("--combo <name>", t("chat.combo"))
+    .option("--responses-api", t("chat.responses_api"))
+    .option("--stream", t("chat.stream"))
+    .option("--no-history", t("chat.no_history"))
+    .action(runChatCommand);
+}
+
+export async function runChatCommand(promptArg, opts, cmd) {
+  const globalOpts = cmd.optsWithGlobals();
+  const prompt = await resolvePrompt(promptArg, opts);
+  if (!prompt) {
+    process.stderr.write(t("chat.error.empty_prompt") + "\n");
+    process.exit(2);
+  }
+
+  const messages = [];
+  if (opts.system) messages.push({ role: "system", content: opts.system });
+  messages.push({ role: "user", content: prompt });
+
+  const body = {
+    model: opts.model,
+    messages,
+    ...(opts.maxTokens && { max_tokens: opts.maxTokens }),
+    ...(opts.temperature != null && { temperature: opts.temperature }),
+    ...(opts.topP != null && { top_p: opts.topP }),
+    ...(opts.reasoningEffort && { reasoning_effort: opts.reasoningEffort }),
+    ...(opts.thinkingBudget && { thinking: { budget_tokens: opts.thinkingBudget } }),
+    ...(opts.combo && { combo: opts.combo }),
+    stream: !!opts.stream,
+  };
+
+  const endpoint = opts.responsesApi ? "/v1/responses" : "/v1/chat/completions";
+
+  const startedAt = Date.now();
+  const response = await apiFetch(endpoint, {
+    method: "POST",
+    body,
+    acceptNotOk: true,
+    timeout: globalOpts.timeout,
+  });
+
+  if (!response.ok) {
+    const errText = await response.text().catch(() => "");
+    process.stderr.write(`\x1b[31m✖ ${response.status} ${response.statusText}\x1b[0m\n`);
+    if (errText) process.stderr.write(errText + "\n");
+    process.exit(1);
+  }
+
+  const latencyMs = Date.now() - startedAt;
+
+  if (opts.stream) {
+    return streamHandle(response, opts.responsesApi);
+  }
+
+  const data = await response.json();
+  const text = extractText(data, opts.responsesApi);
+
+  if (!opts.noHistory) {
+    appendHistory({ prompt, model: opts.model, latencyMs, usage: data.usage, response: text });
+  }
+
+  if (globalOpts.output === "json") {
+    emit(data, globalOpts);
+  } else if (globalOpts.output === "markdown") {
+    console.log(
+      `# Response\n\n${text}\n\n## Metadata\n- Model: ${data.model}\n- Latency: ${latencyMs}ms\n- Usage: ${JSON.stringify(data.usage)}\n`
+    );
+  } else {
+    console.log(text);
+    if (!globalOpts.quiet) {
+      process.stderr.write(
+        `\n[${data.model} · ${latencyMs}ms · ${data.usage?.total_tokens ?? "?"} tok]\n`
+      );
+    }
+  }
+}
+
+async function resolvePrompt(arg, opts) {
+  if (opts.file) return readFileSync(opts.file, "utf8").trim();
+  if (opts.stdin) return readStdin();
+  return arg?.trim() || "";
+}
+
+function readStdin() {
+  return new Promise((resolve) => {
+    let buf = "";
+    process.stdin.setEncoding("utf8");
+    process.stdin.on("data", (c) => (buf += c));
+    process.stdin.on("end", () => resolve(buf.trim()));
+  });
+}
+
+function extractText(data, isResponses) {
+  if (isResponses) {
+    return data.output?.[0]?.content?.[0]?.text ?? data.output_text ?? "";
+  }
+  return data.choices?.[0]?.message?.content ?? "";
+}
+
+async function streamHandle(response, isResponses) {
+  const reader = response.body.getReader();
+  const decoder = new TextDecoder();
+  let buffer = "";
+
+  while (true) {
+    const { done, value } = await reader.read();
+    if (done) break;
+    buffer += decoder.decode(value, { stream: true });
+    const lines = buffer.split("\n");
+    buffer = lines.pop() ?? "";
+
+    for (const line of lines) {
+      if (!line.startsWith("data: ")) continue;
+      const chunk = line.slice(6).trim();
+      if (chunk === "[DONE]") {
+        process.stdout.write("\n");
+        return;
+      }
+      try {
+        const obj = JSON.parse(chunk);
+        const content = isResponses ? obj.delta?.content : obj.choices?.[0]?.delta?.content;
+        if (content) process.stdout.write(content);
+      } catch {}
+    }
+  }
+  process.stdout.write("\n");
+}
+
+function appendHistory(entry) {
+  try {
+    appendFileSync(
+      resolveHistoryPath(),
+      JSON.stringify({ ts: new Date().toISOString(), ...entry }) + "\n"
+    );
+  } catch {
+    // history write failures are non-fatal
+  }
+}
diff --git a/bin/cli/commands/registry.mjs b/bin/cli/commands/registry.mjs
index 0d999c3008..67f083c6ae 100644
--- a/bin/cli/commands/registry.mjs
+++ b/bin/cli/commands/registry.mjs
@@ -1,3 +1,4 @@
+import { registerChat } from "./chat.mjs";
 import { registerServe } from "./serve.mjs";
 import { registerStop } from "./stop.mjs";
 import { registerRestart } from "./restart.mjs";
@@ -25,6 +26,7 @@ import { registerTestProvider } from "./test-provider.mjs";
 import { registerCompletion } from "./completion.mjs";
 
 export function registerCommands(program) {
+  registerChat(program);
   registerServe(program);
   registerStop(program);
   registerRestart(program);
diff --git a/bin/cli/locales/en.json b/bin/cli/locales/en.json
index f4f55306ec..e654d8acd2 100644
--- a/bin/cli/locales/en.json
+++ b/bin/cli/locales/en.json
@@ -54,6 +54,25 @@
     "noKeys": "No keys configured.",
     "confirmRemove": "Remove key {id}?"
   },
+  "chat": {
+    "description": "Send a one-shot chat prompt to OmniRoute",
+    "file": "Read prompt from file",
+    "stdin": "Read prompt from stdin",
+    "system": "System prompt",
+    "model": "Model ID (default: auto)",
+    "max_tokens": "Maximum tokens in response",
+    "temperature": "Sampling temperature (0–2)",
+    "top_p": "Top-p nucleus sampling",
+    "reasoning_effort": "Reasoning effort level (low|medium|high)",
+    "thinking_budget": "Extended thinking token budget",
+    "combo": "Force a specific combo by name",
+    "responses_api": "Use /v1/responses instead of /v1/chat/completions",
+    "stream": "Stream response incrementally",
+    "no_history": "Do not save to ~/.omniroute/cli-history.jsonl",
+    "error": {
+      "empty_prompt": "Error: prompt is required (positional arg, --file, or --stdin)"
+    }
+  },
   "combo": {
     "title": "Combos",
     "switched": "Active combo: {name}",
diff --git a/bin/cli/locales/pt-BR.json b/bin/cli/locales/pt-BR.json
index d135debc80..9e7c2510df 100644
--- a/bin/cli/locales/pt-BR.json
+++ b/bin/cli/locales/pt-BR.json
@@ -54,6 +54,25 @@
     "noKeys": "Nenhuma chave configurada.",
     "confirmRemove": "Remover chave {id}?"
   },
+  "chat": {
+    "description": "Enviar um prompt único ao OmniRoute",
+    "file": "Ler prompt de arquivo",
+    "stdin": "Ler prompt da entrada padrão",
+    "system": "Prompt de sistema",
+    "model": "ID do modelo (padrão: auto)",
+    "max_tokens": "Máximo de tokens na resposta",
+    "temperature": "Temperatura de amostragem (0–2)",
+    "top_p": "Amostragem nucleus top-p",
+    "reasoning_effort": "Nível de esforço de raciocínio (low|medium|high)",
+    "thinking_budget": "Budget de tokens para raciocínio estendido",
+    "combo": "Forçar um combo específico pelo nome",
+    "responses_api": "Usar /v1/responses em vez de /v1/chat/completions",
+    "stream": "Transmitir resposta incrementalmente",
+    "no_history": "Não salvar em ~/.omniroute/cli-history.jsonl",
+    "error": {
+      "empty_prompt": "Erro: prompt obrigatório (argumento posicional, --file ou --stdin)"
+    }
+  },
   "combo": {
     "title": "Combos",
     "switched": "Combo ativo: {name}",
diff --git a/tests/unit/cli-chat.test.ts b/tests/unit/cli-chat.test.ts
new file mode 100644
index 0000000000..e6e34d38ae
--- /dev/null
+++ b/tests/unit/cli-chat.test.ts
@@ -0,0 +1,168 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { tmpdir } from "node:os";
+import { mkdtempSync, readFileSync, existsSync, writeFileSync } from "node:fs";
+import { join } from "node:path";
+
+function mockFetch(body: unknown, status = 200) {
+  return () =>
+    Promise.resolve(
+      new Response(JSON.stringify(body), {
+        status,
+        headers: { "content-type": "application/json" },
+      })
+    );
+}
+
+async function captureStdout(fn: () => Promise<void>): Promise<string> {
+  const chunks: string[] = [];
+  const orig = process.stdout.write.bind(process.stdout);
+  process.stdout.write = (chunk: string | Uint8Array) => {
+    chunks.push(typeof chunk === "string" ? chunk : chunk.toString());
+    return true;
+  };
+  try {
+    await fn();
+  } finally {
+    process.stdout.write = orig;
+  }
+  return chunks.join("");
+}
+
+const FAKE_RESPONSE = {
+  id: "chatcmpl-abc",
+  model: "claude-sonnet-4-6",
+  choices: [{ message: { role: "assistant", content: "Hello!" } }],
+  usage: { prompt_tokens: 5, completion_tokens: 10, total_tokens: 15 },
+};
+
+test("runChatCommand imprime texto da resposta no stdout", async () => {
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-test-"));
+  process.env.DATA_DIR = tmpDir;
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = mockFetch(FAKE_RESPONSE) as any;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "text", quiet: false }) };
+  const out = await captureStdout(() =>
+    runChatCommand("hi", { model: "auto", noHistory: true }, cmd as any)
+  );
+
+  globalThis.fetch = origFetch;
+  delete process.env.DATA_DIR;
+  assert.ok(out.includes("Hello!"));
+});
+
+test("runChatCommand com --output json emite body completo", async () => {
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-test-"));
+  process.env.DATA_DIR = tmpDir;
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = mockFetch(FAKE_RESPONSE) as any;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "json", quiet: true }) };
+  const out = await captureStdout(() =>
+    runChatCommand("hi", { model: "auto", noHistory: true }, cmd as any)
+  );
+
+  globalThis.fetch = origFetch;
+  delete process.env.DATA_DIR;
+  assert.equal(JSON.parse(out).id, "chatcmpl-abc");
+});
+
+test("runChatCommand lê prompt de arquivo com --file", async () => {
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-test-"));
+  const promptFile = join(tmpDir, "prompt.txt");
+  writeFileSync(promptFile, "file prompt content");
+  process.env.DATA_DIR = tmpDir;
+
+  let capturedBody: any = null;
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = ((url: string, init: any) => {
+    capturedBody = JSON.parse(init.body);
+    return Promise.resolve(new Response(JSON.stringify(FAKE_RESPONSE), { status: 200 }));
+  }) as any;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "text", quiet: true }) };
+  await captureStdout(() =>
+    runChatCommand(undefined, { model: "auto", file: promptFile, noHistory: true }, cmd as any)
+  );
+
+  globalThis.fetch = origFetch;
+  delete process.env.DATA_DIR;
+  assert.equal(capturedBody.messages[0].content, "file prompt content");
+});
+
+test("runChatCommand salva histórico em cli-history.jsonl", async () => {
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-hist-"));
+  process.env.DATA_DIR = tmpDir;
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = mockFetch(FAKE_RESPONSE) as any;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "text", quiet: true }) };
+  await captureStdout(() => runChatCommand("save this", { model: "auto" }, cmd as any));
+
+  globalThis.fetch = origFetch;
+
+  const histPath = join(tmpDir, "cli-history.jsonl");
+  assert.ok(existsSync(histPath));
+  const line = JSON.parse(readFileSync(histPath, "utf8").trim().split("\n")[0]);
+  assert.equal(line.prompt, "save this");
+  assert.ok(line.ts);
+  delete process.env.DATA_DIR;
+});
+
+test("runChatCommand usa /v1/responses com --responses-api", async () => {
+  const responsesBody = {
+    id: "resp-abc",
+    output: [{ content: [{ text: "Responses API response" }] }],
+    usage: { total_tokens: 10 },
+    model: "auto",
+  };
+  let capturedUrl = "";
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = ((url: string, init: any) => {
+    capturedUrl = url;
+    return Promise.resolve(new Response(JSON.stringify(responsesBody), { status: 200 }));
+  }) as any;
+
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-test-"));
+  process.env.DATA_DIR = tmpDir;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "text", quiet: true }) };
+  const out = await captureStdout(() =>
+    runChatCommand("test", { model: "auto", responsesApi: true, noHistory: true }, cmd as any)
+  );
+
+  globalThis.fetch = origFetch;
+  delete process.env.DATA_DIR;
+  assert.ok(capturedUrl.includes("/v1/responses"));
+  assert.ok(out.includes("Responses API response"));
+});
+
+test("runChatCommand propaga system prompt no payload", async () => {
+  let capturedBody: any = null;
+  const origFetch = globalThis.fetch;
+  globalThis.fetch = ((url: string, init: any) => {
+    capturedBody = JSON.parse(init.body);
+    return Promise.resolve(new Response(JSON.stringify(FAKE_RESPONSE), { status: 200 }));
+  }) as any;
+
+  const tmpDir = mkdtempSync(join(tmpdir(), "chat-test-"));
+  process.env.DATA_DIR = tmpDir;
+
+  const { runChatCommand } = await import("../../bin/cli/commands/chat.mjs");
+  const cmd = { optsWithGlobals: () => ({ output: "text", quiet: true }) };
+  await captureStdout(() =>
+    runChatCommand("hi", { model: "auto", system: "Be concise", noHistory: true }, cmd as any)
+  );
+
+  globalThis.fetch = origFetch;
+  delete process.env.DATA_DIR;
+  assert.equal(capturedBody.messages[0].role, "system");
+  assert.equal(capturedBody.messages[0].content, "Be concise");
+  assert.equal(capturedBody.messages[1].content, "hi");
+});