> ## Documentation Index
> Fetch the complete documentation index at: https://docs.symmetry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# STE MCP troubleshooting

> Fix a server you cannot reach, a redirect_mismatch after sign-in, tools that never appear, expired tokens, and blocked requests — or reset the connection and start over.

This article covers the most common issues when installing and using the STE MCP.

## Quick diagnosis

| You see…                                                  | Jump to                                                                                        |
| --------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
| Server couldn't be reached / connection failure           | [Cannot Reach the MCP Server](#1-cannot-reach-the-mcp-server)                                  |
| <br />`redirect_mismatch` or `invalid_redirect_uri`<br /> | [redirect\_mismatch After Sign-In](#2-redirect-mismatch-or-invalid-redirect-uri-after-sign-in) |
| MCP isn't available / tools missing after install         | [Tools Not Showing Up After Installation](#3-tools-not-showing-up-after-installation)          |
| Unexpected sign-in prompt / token expired                 | [Token Expired / Prompted to Sign In Again](#4-token-expired-prompted-to-sign-in-again)        |
| <br />`403` / Request blocked                             | [403 / Request Blocked Error](#5-403-request-blocked-error)                                    |
| Need to remove or reset the MCP                           | [Removing or Resetting the STE MCP](#6-removing-or-resetting-the-ste-mcp)                      |

## 1. Cannot reach the MCP server

**Symptom:** *"The MCP server couldn't be reached"* or a connection failure on first call.

**Cause:** Your network is blocking outbound traffic to `mcp.symmetry.com`. This is common with corporate VPNs that have split-tunneling misconfigured.

**Resolution:**

1. Try from a different network (home Wi-Fi or mobile hotspot) to isolate whether the issue is network-specific.
2. If it works off-VPN but not on, ask your network/IT team to allow traffic to `mcp.symmetry.com`.

## 2. `redirect_mismatch` or `invalid_redirect_uri` after sign-in

**Symptom:** *Browser opens, you sign in, but you see*`redirect_mismatch`*or*`invalid redirect_uri`*.*

**Cause:** Symmetry's OAuth allowlist only accepts port 33418 as a redirect target. If your client uses a different port, the auth flow fails.

**Resolution:**

1. **Claude Code:** Remove and re-add the MCP with the `--callback-port 33418` flag, then restart Claude Code.
   ```text theme={null}
   claude mcp remove ste
   claude mcp add ste --transport http https://mcp.symmetry.com/ste --callback-port 33418
   ```
2. **Cursor:** This is unusual. Cursor uses port 33418 by default. Open Cursor's **Developer Tools → Console** and check the actual redirect URL it tried and update.
3. **Gemini CLI:** Confirm your `settings.json` has `redirectUri` set explicitly (for example, `http://localhost:33418/oauth/callback`).

## 3. Tools not showing up after installation

**Symptom:** *"The ste MCP isn't available"* even though you just added it.

**Cause:** The MCP was registered but the client session has not reloaded it yet.

**Resolution:**

1. **Cursor:** Go to **Settings → MCP** and check that `ste` has a green dot. If it's red or yellow, click into it to see the error message.
2. **Claude Code:** Run `claude mcp list` to confirm `ste` is registered. If it appears in the list but tools aren't available in your current chat, you forgot to restart. Exit the session (`/exit` or close the terminal) and start a fresh one.
3. **Gemini CLI:** Confirm your `settings.json` is valid JSON (no trailing commas, all brackets closed) and restart the CLI.

**Note:** Claude Code only loads MCPs at startup. Any time you add, remove, or change an MCP, you must restart the session.

## 4. Token expired / prompted to sign in again

**Symptom:** *"Token expired"* or an unexpected browser sign-in prompt mid-session.

**Cause:** The access token lives 60 minutes; the refresh token lives 24 hours. After 24 hours of inactivity, the full sign-in flow repeats.

**Resolution:**

1. This is normal and expected. Simply complete the sign-in flow in the browser.
2. The browser tab will close automatically after authentication and your client will resume.

**Note:** Token lifetime cannot be extended — this is by design for security.

## 5. 403 / request blocked error

**Symptom:** *A tool call fails with a 403 "Request blocked" error.*

**Cause:** Symmetry's edge security filter blocked the request. This typically means the request body is over 64 KB, or it contains patterns the filter treats as suspicious (for example, SQL-like strings).

**Resolution:**

1. Check whether the request body is unusually large. Multi-employee batch calls can hit the limit.
2. If the request appears well-formed and small, [share the failing request with our team](https://support.symmetry.com/hc/en-us/requests/new) and we can help troubleshoot.

## 6. Removing or resetting the STE MCP

**Use this when:** you need to disconnect, reconfigure, or reset the MCP to a clean state.

**Cursor:** Go to **Settings → MCP**, click the `ste` entry, and select **Remove**. Or delete the `ste` entry from `~/.cursor/mcp.json`.

**Claude Code:**

```text theme={null}
claude mcp remove ste
```

Then restart Claude Code so the change takes effect.

**Gemini CLI:** Remove the `ste-mcp` block from `~/.gemini/settings.json` and restart the CLI.

## Still stuck?

If none of the above resolves your issue:

* [Reach out to our team](https://support.symmetry.com/hc/en-us/requests/new) with a description of the error, the client you're using, and (if available) the failing request payload and timestamp.
* For authentication issues, include the full error message shown in the browser or terminal.