Run a local Diagnosis for an incident
Use a local client, such as Codex or Claude, with an MCP server that connects it to Tellagen. Then run an incident Diagnosis and review the saved result.
On this page
Before you start
Intended audience
Incident commanders and responders who investigate an active incident.
Required permissions
You need an active responder seat. The Local Diagnosis preset includes incidents:read, incidents:write, slack_context:read, services:read, teams:read, and custom_fields:read.
Prerequisites
- Install Codex CLI or Claude Code on the computer that will run the investigation.
- Sign in to the correct Tellagen workspace.
- A local client is Codex or Claude running on your computer.
- An MCP server lets the local client call Tellagen or a provider tool.
- A provider tool gives the client read-only access to an evidence source, such as monitoring or infrastructure.
- Already configured? Start at Check local setup.
Procedure
Prepare the client
Step 1 of 13
Open local investigation tools
Open Settings. The navigation label is Local investigation tools. The page heading is AI diagnostics.
Step 2 of 13
Choose a client
Select Codex or Claude. Tellagen shows instructions for that client.

Choose a client before you copy its setup command. Open full-size image(opens in a new tab) Step 3 of 13
Create the API key
Create a key with the Local Diagnosis preset. Store the token immediately because Tellagen shows it once.

The preset supplies the scopes needed by a local Diagnosis run. Open full-size image(opens in a new tab) Step 4 of 13
Copy the Tellagen command
Find the Tellagen MCP card. Select Copy.

Copy the Tellagen MCP command for the selected local client. Open full-size image(opens in a new tab) Step 5 of 13
Add required provider tools
Add only the provider MCP tools that the investigation needs. Keep their credentials in your local client.
Step 6 of 13
Check local setup
Select Check MCP tools. Paste the generated diagnostic prompt into your local client.
Codex configuration check
shellcodex mcp listClaude configuration check
shellclaude mcp list claude mcp get tellagenStep 7 of 13
Review the setup result
Return to Tellagen. Make sure that required cards show INSTALLED and ACCESS OK. Review each stale result before use.
Run the investigation
Step 8 of 13
Open Diagnosis
Open the incident. Select Diagnosis.
Step 9 of 13
Choose the run relationship
Select New independent run for a separate investigation. Select Follow up on this run to continue the selected result.
Step 10 of 13
Set the focus
Enter one focused question. Include the failed behavior, relevant service, and time window.
Step 11 of 13
Choose evidence
Open Evidence options. Enable Include incident Slack context only when the channel context is necessary.
Step 12 of 13
Start the handoff
Select Run diagnosis. Copy the start command into your local client. Tellagen shows the run as waiting for local work.
Review the result
Step 13 of 13
Review the saved result
Review Investigation result, Evidence and checks, Run details, and Raw local tool trace. Separate observed evidence from suggestions.
You are done when…
Tellagen stores the local run, checked evidence, findings, and trace on the incident.
Troubleshooting
The page says No diagnostic tools are available for this client.
Choose the client you installed, then copy and run the matching command from the MCP tool gallery.
Codex shows Auth: Unsupported for the local connection.
This status is expected for this local connection. Tellagen authentication uses TELLAGEN_API_KEY in the local MCP configuration.
Run diagnosis is not available after setup.
Confirm that the Local Diagnosis API key was created from the preset, that its owner has an active responder seat, and that the Tellagen MCP connection uses that key.
Diagnosis ended early or is inconclusive.
Review Tool activity and the missing evidence in the Diagnosis tab. Fix the local tool or credential setup, then run a new diagnosis or a follow-up diagnosis.
A required tool does not show INSTALLED.
Run the install command for the selected client. Then run Check MCP tools again.
A tool shows a stale result.
Run the generated diagnostic prompt again. Use the result only after its status is current.
The local client cannot call Tellagen.
The incident record and saved investigation results stay in Tellagen. Make sure that the key uses the Local Diagnosis preset and that the workspace URL is correct. Run Check MCP tools again. If access still fails, ask a workspace settings administrator to review the key and local setup. Then email Tellagen support.
Related articles
- Recommended next taskSupport Center
- API reference
- Configure Codex for Diagnosis
- Review Diagnosis findings
External setup references
- OpenAI Codex MCP documentation(opens in a new tab) (verified 2026-08-29)
- Anthropic Claude Code MCP documentation(opens in a new tab) (verified 2026-08-29)