diff --git a/docs/user-docs/configuration.md b/docs/user-docs/configuration.md
index 00512fa22..182e2f5d9 100644
--- a/docs/user-docs/configuration.md
+++ b/docs/user-docs/configuration.md
@@ -148,6 +148,7 @@ Recommended verification order:
 
 - Use absolute paths for local executables and scripts when possible.
 - For `stdio` servers, prefer setting required environment variables directly in the MCP config instead of relying on an interactive shell profile.
+- GSD and `gsd-mcp-server` both hydrate supported tool keys saved in `~/.gsd/agent/auth.json`, so MCP configs can safely reference them through `${ENV_VAR}` placeholders without committing raw credentials.
 - If a server is team-shared and safe to commit, `.mcp.json` is usually the better home.
 - If a server depends on machine-local paths, personal services, or local-only secrets, prefer `.gsd/mcp.json`.
 
diff --git a/packages/mcp-server/README.md b/packages/mcp-server/README.md
index f1544b895..e6f03ddcd 100644
--- a/packages/mcp-server/README.md
+++ b/packages/mcp-server/README.md
@@ -234,6 +234,8 @@ Resolve a pending blocker in a session by sending a response to the blocked UI r
 | `GSD_CLI_PATH` | Absolute path to the GSD CLI binary. If not set, the server resolves `gsd` via `which`. |
 | `GSD_WORKFLOW_EXECUTORS_MODULE` | Optional absolute path or `file:` URL for the shared GSD workflow executor module used by workflow mutation tools. |
 
+The server also hydrates supported tool credentials from `~/.gsd/agent/auth.json` on startup. Keys saved through `/gsd config` become available to the MCP server process automatically, and any explicitly-set environment variable still wins.
+
 ## Architecture
 
 ```
diff --git a/packages/mcp-server/src/cli.ts b/packages/mcp-server/src/cli.ts
index 141c4083f..14f341b1f 100644
--- a/packages/mcp-server/src/cli.ts
+++ b/packages/mcp-server/src/cli.ts
@@ -7,10 +7,13 @@
 
 import { SessionManager } from './session-manager.js';
 import { createMcpServer } from './server.js';
+import { loadStoredToolEnvKeys } from './tool-credentials.js';
 
 const MCP_PKG = '@modelcontextprotocol/sdk';
 
 async function main(): Promise<void> {
+  loadStoredToolEnvKeys();
+
   const sessionManager = new SessionManager();
 
   // Create the configured MCP server with session, interactive, read-only,
diff --git a/packages/mcp-server/src/tool-credentials.test.ts b/packages/mcp-server/src/tool-credentials.test.ts
new file mode 100644
index 000000000..bc06a8a13
--- /dev/null
+++ b/packages/mcp-server/src/tool-credentials.test.ts
@@ -0,0 +1,66 @@
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { mkdtempSync, mkdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+import { loadStoredToolEnvKeys, resolveAuthPath } from "./tool-credentials.js";
+
+describe("tool credentials", () => {
+  it("hydrates supported keys from auth.json", () => {
+    const tempRoot = mkdtempSync(join(tmpdir(), "gsd-mcp-auth-"));
+    const authPath = join(tempRoot, "auth.json");
+    const env: NodeJS.ProcessEnv = {};
+
+    try {
+      writeFileSync(authPath, JSON.stringify({
+        tavily: { type: "api_key", key: "tvly-secret" },
+        context7: [{ type: "api_key", key: "ctx7-secret" }],
+        anthropic: { type: "api_key", key: "sk-ant-ignore" },
+      }));
+
+      const loaded = loadStoredToolEnvKeys({ authPath, env });
+      assert.deepEqual(loaded.sort(), ["CONTEXT7_API_KEY", "TAVILY_API_KEY"]);
+      assert.equal(env.TAVILY_API_KEY, "tvly-secret");
+      assert.equal(env.CONTEXT7_API_KEY, "ctx7-secret");
+      assert.equal(env.ANTHROPIC_API_KEY, undefined);
+    } finally {
+      rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+
+  it("does not overwrite explicit environment variables", () => {
+    const tempRoot = mkdtempSync(join(tmpdir(), "gsd-mcp-auth-"));
+    const authPath = join(tempRoot, "auth.json");
+    const env: NodeJS.ProcessEnv = {
+      BRAVE_API_KEY: "already-set",
+    };
+
+    try {
+      writeFileSync(authPath, JSON.stringify({
+        brave: { type: "api_key", key: "from-auth-json" },
+      }));
+
+      const loaded = loadStoredToolEnvKeys({ authPath, env });
+      assert.deepEqual(loaded, []);
+      assert.equal(env.BRAVE_API_KEY, "already-set");
+    } finally {
+      rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+
+  it("resolves auth.json from GSD_CODING_AGENT_DIR", () => {
+    const tempRoot = mkdtempSync(join(tmpdir(), "gsd-mcp-agent-dir-"));
+    const agentDir = join(tempRoot, "agent");
+    mkdirSync(agentDir, { recursive: true });
+
+    try {
+      assert.equal(
+        resolveAuthPath({ GSD_CODING_AGENT_DIR: agentDir }),
+        join(agentDir, "auth.json"),
+      );
+    } finally {
+      rmSync(tempRoot, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/packages/mcp-server/src/tool-credentials.ts b/packages/mcp-server/src/tool-credentials.ts
new file mode 100644
index 000000000..818b87d6b
--- /dev/null
+++ b/packages/mcp-server/src/tool-credentials.ts
@@ -0,0 +1,79 @@
+import { existsSync, readFileSync } from "node:fs";
+import { homedir } from "node:os";
+import { join } from "node:path";
+
+type AuthCredential =
+  | { type?: unknown; key?: unknown }
+  | Array<{ type?: unknown; key?: unknown }>;
+
+type AuthStorageData = Record<string, AuthCredential>;
+
+const TOOL_ENV_KEYS = [
+  ["brave", "BRAVE_API_KEY"],
+  ["brave_answers", "BRAVE_ANSWERS_KEY"],
+  ["context7", "CONTEXT7_API_KEY"],
+  ["jina", "JINA_API_KEY"],
+  ["tavily", "TAVILY_API_KEY"],
+  ["slack_bot", "SLACK_BOT_TOKEN"],
+  ["discord_bot", "DISCORD_BOT_TOKEN"],
+  ["telegram_bot", "TELEGRAM_BOT_TOKEN"],
+  ["groq", "GROQ_API_KEY"],
+  ["ollama-cloud", "OLLAMA_API_KEY"],
+  ["custom-openai", "CUSTOM_OPENAI_API_KEY"],
+] as const;
+
+function expandHome(pathValue: string): string {
+  if (pathValue === "~") return homedir();
+  if (pathValue.startsWith("~/")) return join(homedir(), pathValue.slice(2));
+  return pathValue;
+}
+
+function getStoredApiKey(data: AuthStorageData, providerId: string): string | undefined {
+  const raw = data[providerId];
+  const credentials = Array.isArray(raw) ? raw : raw ? [raw] : [];
+
+  for (const credential of credentials) {
+    if (credential?.type !== "api_key") continue;
+    if (typeof credential.key !== "string") continue;
+    if (credential.key.trim().length === 0) continue;
+    return credential.key;
+  }
+
+  return undefined;
+}
+
+export function resolveAuthPath(env: NodeJS.ProcessEnv = process.env): string {
+  const agentDir = env.GSD_CODING_AGENT_DIR?.trim();
+  if (agentDir) return join(expandHome(agentDir), "auth.json");
+  return join(homedir(), ".gsd", "agent", "auth.json");
+}
+
+export function loadStoredToolEnvKeys(options: {
+  env?: NodeJS.ProcessEnv;
+  authPath?: string;
+} = {}): string[] {
+  const env = options.env ?? process.env;
+  const authPath = options.authPath ?? resolveAuthPath(env);
+  if (!existsSync(authPath)) return [];
+
+  let parsed: AuthStorageData;
+  try {
+    const raw = readFileSync(authPath, "utf-8");
+    const data = JSON.parse(raw) as unknown;
+    if (!data || typeof data !== "object" || Array.isArray(data)) return [];
+    parsed = data as AuthStorageData;
+  } catch {
+    return [];
+  }
+
+  const loaded: string[] = [];
+  for (const [providerId, envVar] of TOOL_ENV_KEYS) {
+    if (env[envVar]) continue;
+    const key = getStoredApiKey(parsed, providerId);
+    if (!key) continue;
+    env[envVar] = key;
+    loaded.push(envVar);
+  }
+
+  return loaded;
+}