Health Check

Purpose

Diagnose what's working, what's broken, and fix what can be fixed. This is Dex's self-repair system. It reads health data from pre-flight checks and error logs, translates technical failures into plain language, and offers specific fixes.

When to Run

• User types /health-check
• User says "fix health issues" or "something's broken"
• User says "check health" or "system status"
• After session start shows pre-flight warnings
• When an MCP tool fails and user wants to investigate

Execution

Step 1: Gather Health Data

Read both health files silently. Don't show raw JSON to the user.

A. Pre-flight results:

Read: .logs/mcp-health.json

This file contains cached results from the last pre-flight check. Each server entry has:

• status: "ok" or "error"
• error: technical error message (for your diagnosis)
• humanError: plain-language message (for the user)
• checkedAt: when it was last checked

B. Error queue:

Read: .logs/error-queue.json

This file contains recent errors from MCP tool calls. Each entry has:

• source: which MCP server (e.g., "mcp:work-mcp")
• severity: "error" or "warning"
• message: technical error (for your diagnosis)
• humanMessage: plain-language message (for the user)
• context.tool: which tool was called
• timestamp: when it happened
• count: how many times (deduped within 5-minute windows)
• acknowledged: whether user has been told about it

C. If either file is missing:

If .logs/mcp-health.json doesn't exist, the pre-flight checker hasn't run yet. Note this and offer to run one.

If .logs/error-queue.json doesn't exist, there are no logged errors. This is good news.

If the .logs/ directory doesn't exist at all, the health system hasn't been set up yet. Tell the user:

The health monitoring system isn't set up yet. This is normal if you just updated Dex.

Want me to check your MCP servers manually? I can verify each one is working.

Then skip to Step 5 (manual check).

Step 2: Display Health Summary

Present results in plain language, grouped by severity. Never show raw JSON or stack traces.

If everything is healthy and no unacknowledged errors:

All systems are running fine. Nothing to fix.

Last checked: [relative time, e.g., "2 hours ago"]
MCP servers: [X]/[Y] operational
Recent errors: None

Stop here. Don't pad with unnecessary detail.

If there are issues, show them grouped by severity:

Dex Health Report
━━━━━━━━━━━━━━━━

ERRORS (need attention)

  1. [Server name] — [humanMessage or humanError]
     When: [relative time]  |  Occurrences: [count]
     Tool affected: [tool name, if from error queue]

  2. [Server name] — [humanMessage or humanError]
     When: [relative time]  |  Occurrences: [count]

WARNINGS (worth knowing)

  3. [Server name] — [humanMessage or humanError]
     When: [relative time]

━━━━━━━━━━━━━━━━
[X] issues found  |  [Y] can be auto-fixed

Formatting rules:

• Show errors first, then warnings
• Use the humanMessage or humanError field — never the technical message or error
• Show relative timestamps ("2 hours ago", "yesterday at 3pm") not ISO timestamps
• If count > 1, show it — "Occurrences: 5" tells the user this is a persistent problem
• Combine pre-flight failures and error queue entries for the same server into one item
• Cap display at 10 issues. If more: "...and [N] more. Want to see all?"

Step 3: Diagnose and Propose Fixes

For each issue, analyze the technical message/error field (not shown to user) and propose a specific fix. Use this mapping:

Module/Package Issues:

Config Issues:

File/Permission Issues:

Connection Issues:

Catch-all:

Present fixes as a numbered list tied to each issue:

Recommended fixes:

  1. Granola MCP — missing package
     → Run: pip install -e dex-core
     [Auto-fixable]

  2. Work MCP — task file not found
     → Want me to check if 03-Tasks/Tasks.md exists?
     [Needs investigation]

  3. Career MCP — permission error on evidence file
     → Run: chmod 644 05-Areas/Career/Evidence/2026-Q1.md
     [Manual fix]

Step 4: Offer to Fix

After showing the diagnosis, offer to take action:

Want me to try fixing these? Here's what I can do:

  Auto-fix (I'll handle it):
  • Reinstall Python packages
  • Regenerate missing config from example
  • Create missing vault files (Tasks.md, etc.)
  • Validate and repair .mcp.json

  Manual (you'll need to do this):
  • File permission changes
  • Editor restart
  • API key configuration (/ai-setup)

[Fix what you can] / [Show me details first] / [Skip for now]

If user says "fix what you can":

Execute auto-fixable items in order:

1. Missing packages: Run pip install -e dex-core from the dex-core directory
2. Missing .mcp.json: Copy from .mcp.json.example, substitute VAULT_PATH
3. Invalid .mcp.json: Read it, validate JSON, identify the issue, offer to rewrite
4. Missing vault files: Create with minimal valid content (e.g., empty Tasks.md with headers)
5. Corrupted JSON data files: Read the file, identify the corruption, offer to reset or repair

After each fix, report:

✓ Reinstalled Python packages
✓ Created missing 03-Tasks/Tasks.md
✗ Couldn't fix permission on Evidence file — you'll need to run:
  chmod 644 05-Areas/Career/Evidence/2026-Q1.md

If user says "show me details first":

For each issue, show the full technical context (this is the one time you show technical detail):

Issue #1: Granola MCP — missing package

  Technical error: ModuleNotFoundError: No module named 'granola_server'
  Server config: dex-granola-mcp in .mcp.json
  Last working: 2 days ago

  Fix: pip install -e dex-core

  This reinstalls all MCP server packages. It takes about 10 seconds.

Step 5: Acknowledge Errors

After addressing issues (whether auto-fixed or explained):

Update the error queue:

Read .logs/error-queue.json, set acknowledged: true on every entry that was shown to the user. Write the file back.

This prevents the same errors from resurfacing at the next session start.

Note: If the error queue file doesn't exist or is empty, skip this step.

Step 6: Fresh Re-Check (Optional)

At the end, offer a fresh check:

Want me to run a fresh pre-flight check to verify everything?

If yes:

1. Delete .logs/mcp-health.json (forces re-check)
2. Run the pre-flight checker:

   python3 "$VAULT_PATH/dex-core/core/utils/preflight.py" 2>/dev/null || python3 "core/utils/preflight.py" 2>/dev/null
   

3. Read the newly generated .logs/mcp-health.json
4. Report results:

   Fresh check complete:
   
   ✓ work-mcp — OK
   ✓ calendar-mcp — OK
   ✓ career-mcp — OK
   ✗ granola-mcp — still failing (missing package)
   ✓ dex-improvements-mcp — OK
   ...
   
   [X]/[Y] MCP servers operational
   

If the pre-flight script doesn't exist yet (health system not fully built):

Fall back to manual checks:

# For each server in .mcp.json, try importing the module
python3 -c "import core.mcp.work_server" 2>&1
python3 -c "import core.mcp.calendar_server" 2>&1
# etc.

Report which imports succeed and which fail.

Step 7: Track Usage (Silent)

Update System/usage_log.md to mark health check as used.

Analytics (Silent):

Call track_event with event_name health_check_completed and properties:

• errors_found: number of errors found
• warnings_found: number of warnings found
• auto_fixed: number of issues auto-fixed

This only fires if the user has opted into analytics. No action needed if it returns "analytics_disabled".

Edge Cases

No Health Files Exist

The health system hasn't been set up yet. This is expected for new or recently updated Dex installations.

Offer to do a manual check of MCP servers by testing imports, then report what's working.

Error Queue is Very Large

If error-queue.json has more than 20 unacknowledged entries:

There are [N] unacknowledged errors in the queue. Here are the most recent 10:

[Show top 10 by timestamp]

The older errors are likely symptoms of the same issues. Want me to acknowledge them all after we fix the root causes?

Same Server Appears in Both Files

If a server has both a pre-flight failure AND error queue entries, combine them:

Granola MCP — can't start (missing package)
  Pre-flight: Failed to import at [time]
  Also: 3 tool errors since [time] (task creation, task update, etc.)
  Root cause: Missing Python package — fixing the import will resolve the tool errors too

All Servers Healthy but Errors Exist

This means servers started fine but tools failed during use. Focus on the error queue:

All MCP servers are starting correctly, but some tools had errors recently:

  1. Work MCP — task creation failed (3 times, yesterday)
     This might be a data issue rather than a server problem.
     Want me to investigate the task file?

User Just Wants Quick Status

If user says "is everything working?" or "quick health check":

Give the short version only:

MCP Servers: [X]/[Y] operational
Recent errors: [N] (or "None")
[One-liner about any critical issue, or "Nothing needs attention."]

Don't go into fix mode unless asked.

Related Commands

• /ai-status — Check AI model configuration specifically
• /ai-setup — Configure API keys and model preferences
• /dex-update — Update Dex (often fixes package issues)
• /xray — Understand how Dex's architecture works under the hood