diff --git a/packages/providers/src/deepseekTextProvider.ts b/packages/providers/src/deepseekTextProvider.ts
new file mode 100644
index 0000000..e6cc8f8
--- /dev/null
+++ b/packages/providers/src/deepseekTextProvider.ts
@@ -0,0 +1,55 @@
+import type { ModelProvider, ProviderKind, GenParams, GenResult } from "@executagent/core";
+
+export const TIER_DEEPSEEK_MODEL: Record<GenParams["tier"], string> = {
+  S: "deepseek-chat",
+  M: "deepseek-chat",
+  L: "deepseek-chat",
+};
+
+const API_URL = "https://api.deepseek.com/v1/chat/completions";
+
+export class DeepSeekTextProvider implements ModelProvider {
+  readonly name = "deepseek";
+  constructor(private readonly apiKey: string) {}
+
+  supports(kind: ProviderKind): boolean {
+    return kind === "text";
+  }
+
+  async generate(prompt: string, params: GenParams): Promise<GenResult> {
+    const model = TIER_DEEPSEEK_MODEL[params.tier];
+    const start = performance.now();
+    const res = await fetch(API_URL, {
+      method: "POST",
+      headers: {
+        "content-type": "application/json",
+        "Authorization": `Bearer ${this.apiKey}`,
+      },
+      body: JSON.stringify({
+        model,
+        max_tokens: params.maxTokens ?? 1024,
+        messages: [{ role: "user", content: prompt }],
+      }),
+    });
+    if (!res.ok) {
+      throw new Error(`DeepSeek API ${res.status}: ${await res.text()}`);
+    }
+    const data = await res.json() as {
+      choices: Array<{ message: { content: string } }>;
+      usage?: { prompt_tokens?: number; completion_tokens?: number };
+    };
+    const text = data.choices[0]?.message?.content ?? "";
+    return {
+      kind: "text",
+      text,
+      contentType: "text/plain",
+      model,
+      provider: this.name,
+      usage: {
+        inputTokens: data.usage?.prompt_tokens ?? 0,
+        outputTokens: data.usage?.completion_tokens ?? 0,
+        latencyMs: Math.round(performance.now() - start),
+      },
+    };
+  }
+}
diff --git a/packages/providers/src/index.ts b/packages/providers/src/index.ts
index a11c187..a08ea1b 100644
--- a/packages/providers/src/index.ts
+++ b/packages/providers/src/index.ts
@@ -5,6 +5,7 @@ export * from "./types.ts";
 export * from "./registry.ts";
 export { MockProvider } from "./mockProvider.ts";
 export { ClaudeTextProvider, TIER_TEXT_MODEL } from "./claudeTextProvider.ts";
+export { DeepSeekTextProvider, TIER_DEEPSEEK_MODEL } from "./deepseekTextProvider.ts";
 export { ImageProvider, TIER_IMAGE_PARAMS } from "./imageProvider.ts";
 export { SelfHostedProvider } from "./selfHostedStub.ts";
 export { HashingEmbeddingProvider, lexicalEmbed } from "./embed.ts";
diff --git a/packages/providers/src/registry.test.ts b/packages/providers/src/registry.test.ts
index 864e336..c259b46 100644
--- a/packages/providers/src/registry.test.ts
+++ b/packages/providers/src/registry.test.ts
@@ -2,6 +2,7 @@ import { describe, it, expect } from "vitest";
 import { resolveProvider, configFromEnv, TIER_TEXT_MODEL } from "./registry.ts";
 import { MockProvider } from "./mockProvider.ts";
 import { ClaudeTextProvider } from "./claudeTextProvider.ts";
+import { DeepSeekTextProvider } from "./deepseekTextProvider.ts";
 
 describe("registry", () => {
   it("maps text tiers to distinct Claude models S<M<L", () => {
@@ -29,4 +30,13 @@ describe("registry", () => {
     expect(cfg.anthropicApiKey).toBe("k");
     expect(cfg.forceMock).toBe(true);
   });
+
+  it("uses DeepSeek when only deepseekApiKey is configured", () => {
+    expect(resolveProvider("text", { deepseekApiKey: "sk-test" })).toBeInstanceOf(DeepSeekTextProvider);
+  });
+
+  it("reads DEEPSEEK_API_KEY from env bag", () => {
+    const cfg = configFromEnv({ DEEPSEEK_API_KEY: "sk-ds-test" });
+    expect(cfg.deepseekApiKey).toBe("sk-ds-test");
+  });
 });
diff --git a/packages/providers/src/registry.ts b/packages/providers/src/registry.ts
index 026365d..142e5b5 100644
--- a/packages/providers/src/registry.ts
+++ b/packages/providers/src/registry.ts
@@ -4,6 +4,7 @@
 import type { ModelProvider, ProviderKind } from "@executagent/core";
 import { MockProvider } from "./mockProvider.ts";
 import { ClaudeTextProvider, TIER_TEXT_MODEL } from "./claudeTextProvider.ts";
+import { DeepSeekTextProvider } from "./deepseekTextProvider.ts";
 import { ImageProvider } from "./imageProvider.ts";
 import { HashingEmbeddingProvider } from "./embed.ts";
 
@@ -12,6 +13,7 @@ export { TIER_IMAGE_PARAMS } from "./imageProvider.ts";
 
 export interface ProviderConfig {
   anthropicApiKey?: string;
+  deepseekApiKey?: string;
   imageApiKey?: string;
   imageApiUrl?: string;
   imageModel?: string;
@@ -24,7 +26,9 @@ export function resolveProvider(kind: ProviderKind, cfg: ProviderConfig): ModelP
 
   switch (kind) {
     case "text":
-      return cfg.anthropicApiKey ? new ClaudeTextProvider(cfg.anthropicApiKey) : new MockProvider();
+      if (cfg.anthropicApiKey) return new ClaudeTextProvider(cfg.anthropicApiKey);
+      if (cfg.deepseekApiKey)  return new DeepSeekTextProvider(cfg.deepseekApiKey);
+      return new MockProvider();
     case "image":
       return cfg.imageApiKey && cfg.imageApiUrl
         ? new ImageProvider({ apiKey: cfg.imageApiKey, apiUrl: cfg.imageApiUrl, ...(cfg.imageModel ? { model: cfg.imageModel } : {}) })
@@ -41,6 +45,7 @@ export function resolveProvider(kind: ProviderKind, cfg: ProviderConfig): ModelP
 export function configFromEnv(env: Record<string, string | undefined>): ProviderConfig {
   const cfg: ProviderConfig = {};
   if (env.ANTHROPIC_API_KEY) cfg.anthropicApiKey = env.ANTHROPIC_API_KEY;
+  if (env.DEEPSEEK_API_KEY) cfg.deepseekApiKey = env.DEEPSEEK_API_KEY;
   if (env.IMAGE_API_KEY) cfg.imageApiKey = env.IMAGE_API_KEY;
   if (env.IMAGE_API_URL) cfg.imageApiUrl = env.IMAGE_API_URL;
   if (env.IMAGE_MODEL) cfg.imageModel = env.IMAGE_MODEL;