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Demo: Cross-Session Context Memory

You're building a React app. Yesterday you spent 2 hours debugging an auth token refresh issue with Copilot. Today you open a new session — will the AI remember?

Scenario Setup

# You have a React + Node.js project
cd my-react-app
fcontext init
fcontext enable copilot

Day 1 — Debugging Session

You ask Copilot to help debug a token refresh loop. After 2 hours of investigation, the AI discovers:

  • The refresh token endpoint returns a new access token but the client stores it in the wrong key
  • There's a race condition when two API calls trigger refresh simultaneously
  • The fix: add a mutex lock + fix the storage key

The AI writes its findings to .fcontext/_topics/:

.fcontext/_topics/
  auth-token-refresh-bug.md

Inside auth-token-refresh-bug.md:

# Auth Token Refresh Bug — Root Cause Analysis

## Problem
Token refresh loop caused by two issues:
1. Client stores refreshed token in `sessionStorage.token` 
   but reads from `sessionStorage.access_token`
2. Race condition: concurrent API calls each trigger 
   independent refresh, overwriting each other

## Fix Applied
- Added refresh mutex in `src/auth/tokenManager.ts`
- Fixed storage key to `access_token` consistently
- Added 5s debounce on refresh trigger

## Files Changed
- src/auth/tokenManager.ts (mutex + key fix)
- src/api/client.ts (debounce)

Day 2 — New Session

You open VS Code the next morning. New session, clean slate — except it isn't.

The AI reads .fcontext/_topics/auth-token-refresh-bug.md on startup.

You ask:

"Is there anything else related to the token refresh that we should test?"

The AI immediately responds with edge cases — because it remembers the mutex, the race condition, and the exact files involved. No re-explanation needed.

Day 3 — Switch to Claude Code

You want to try Claude Code for a different perspective:

fcontext enable claude

Claude reads the same .fcontext/_topics/ and instantly knows about the auth fix, the mutex pattern, and the file locations. You ask:

"Can you review the token refresh fix for potential edge cases?"

Claude reviews src/auth/tokenManager.ts with full knowledge of why the mutex was added.

What Made This Work

sequenceDiagram participant D1 as Day 1 (Copilot) participant FC as .fcontext/_topics/ participant D2 as Day 2 (Copilot) participant D3 as Day 3 (Claude) D1->>FC: Write auth-token-refresh-bug.md D1->>FC: Update _README.md D2->>FC: Read topics + README Note over D2: Full context restored D3->>FC: Read same topics + README Note over D3: Same context, different agent

Key takeaway: The AI wrote one topic file during debugging. That file persisted across sessions and agents — turning a 2-hour debugging session into permanent project knowledge.

Try It Yourself

pip install fcontext
cd your-project
fcontext init
fcontext enable copilot   # or your preferred agent

# Start working — the AI will create topics automatically
# Come back tomorrow — context is preserved