tomoyaf

Posted on Feb 9

I Built a Tool That Lets Claude Read My Terminal Logs — Here's Why You Need One Too

#ai #devops #opensource #programming

We're living in the golden age of AI-assisted coding.

Claude can refactor your functions. Copilot can write your tests. Cursor can navigate your entire codebase.

But ask any of them: "What was that error I saw 5 minutes ago?"

Silence.

AI can read your code. But it's completely blind to your runtime.

That's the problem I solved with logifai.

The Moment I Knew I Had to Build This

I was debugging a race condition. The bug appeared maybe once every 50 requests — completely random.

After 2 hours of watching logs scroll by, I finally caught it:

[ERROR] Connection timeout: pool exhausted after 30000ms
        at ConnectionPool.acquire (lib/pool.js:142:15)
        at async QueryRunner.connect (lib/runner.js:87:21)

I immediately asked Claude: "Can you help me fix this connection pool exhaustion?"

Claude asked: "Can you show me the error message and stack trace?"

I scrolled up. And up. And up.

Gone. Swallowed by 10,000 lines of HTTP request logs.

I spent the next 20 minutes trying to reproduce the error, just so I could copy-paste it.

That night, I started building logifai.

What is logifai?

logifai is a zero-dependency CLI tool that:

📥 Captures your terminal output via pipe
🔄 Normalizes logs into a consistent format
🔒 Redacts secrets automatically (API keys, tokens, passwords)
🌐 Serves a real-time Web UI
🤖 Integrates with Claude Code via a Skill

One line changes your debugging workflow forever:

npm run dev 2>&1 | logifai

That's it. Every log is now searchable by AI.

See It In Action

Step 1: Pipe Your Command

$ npm run dev 2>&1 | logifai

📡 logifai v0.1.0
📁 Session: a1b2c3d4
🌐 Web UI: http://localhost:3100
⏳ Capturing stdin...

Step 2: Errors Happen (They Always Do)

Your app crashes. A stack trace flies by at 100 lines per second.

Normally, you'd panic-scroll or pray your terminal buffer is big enough.

Not anymore.

Step 3: Ask Claude

With the Claude Code Skill installed, just ask:

You: What errors happened in my last session?

Claude: I found 3 errors in session a1b2c3d4:

Line 142: TypeError: Cannot read property 'id' of undefined

Location: src/api/users.ts:47

Line 287: ECONNREFUSED 127.0.0.1:5432

PostgreSQL connection failed

Line 512: JsonWebTokenError: jwt malformed

Authentication middleware rejected the token

Want me to investigate any of these?

Claude now sees what your terminal saw.

The Web UI

logifai automatically opens a Web UI at http://localhost:3100:

Feature	Description
Live streaming	Logs appear in real-time via Server-Sent Events
Level filtering	Toggle ERROR / WARN / INFO / DEBUG
Keyword search	Find specific messages instantly
Line references	Click any line to copy a `logifai://` URI
Shift+click	Select a range of lines

No React. No npm install. No webpack. Just HTML served from a single TypeScript file.

Log References: Share Exact Lines

Every session gets a unique ID. Every line gets a number.

This creates precise, shareable references:

logifai://a1b2c3d4:142-150

Translation: "Session a1b2c3d4, lines 142 through 150"

What You Can Do With References

In your terminal:

$ logifai show logifai://a1b2c3d4:142-150

142: [ERROR] Connection refused
143:     at Socket.connect (net.js:1141:16)
144:     at DBClient.connect (client.js:89:12)
...

In GitHub issues:

The error occurs at logifai://a1b2c3d4:142. See attached logs.

With Claude:

Explain this error: logifai://a1b2c3d4:142-150

Automatic Secret Redaction

Logs leak secrets. It happens to everyone.

logifai automatically detects and redacts sensitive data:

Pattern	Before	After
AWS Keys	`AKIAIOSFODNN7EXAMPLE`	`[AWS_KEY]`
OpenAI Keys	`sk-proj-abc123def456...`	`[API_KEY]`
Bearer Tokens	`Bearer eyJhbGciOiJ...`	`Bearer [TOKEN]`
Database URLs	`postgres://user:secret@host`	`postgres://user:[REDACTED]@host`
Private Keys	`-----BEGIN RSA PRIVATE`	`[PRIVATE_KEY]`

Your logs never leave your machine. No cloud. No telemetry. No tracking.

Storage location: ~/.local/state/logifai/logs/ (permissions: 600)

The Normalizer: Order From Chaos

Different tools log differently. logifai normalizes them all:

Input (Raw log)

2024-01-15 10:23:45 ERROR Failed to connect
    at Database.connect (db.js:42)
    at Server.start (server.js:15)

Output (NDJSON)

{
  "timestamp": "2024-01-15T10:23:45.000Z",
  "level": "ERROR",
  "message": "Failed to connect",
  "stack": "at Database.connect (db.js:42)\n    at Server.start (server.js:15)",
  "session_id": "a1b2c3d4",
  "git_branch": "feature/auth",
  "git_commit": "7f3a2b1"
}

Supported Formats

Structured JSON — pino, winston, bunyan
Multi-line stack traces — automatically grouped with their errors
Log levels — inferred from keywords when not explicit
Timestamps — ISO 8601, Unix epoch, RFC 3339
Common formats — Apache CLF, Syslog, nginx

Installation

One-Line Install (macOS / Linux)

curl -fsSL https://raw.githubusercontent.com/fujitatomoya/logifai/main/install.sh | bash

What happens:

Detects your OS and CPU architecture
Downloads the correct binary from GitHub Releases
Verifies SHA256 checksum
Installs to ~/.local/bin/ and updates your PATH

Alternative: npm

npm install -g logifai

Enable Claude Code Integration

logifai install-skill

This installs the Skill to ~/.claude/skills/logifai/.

Why These Technical Choices?

Decision	Why
Zero runtime dependencies	No `node_modules`. No supply chain attacks. ~20MB binary.
Bun compile	Single executable. No Node.js required on target machine.
NDJSON storage	Stream-friendly. Grep-able. No database setup.
Server-Sent Events	Simpler than WebSockets. Works through corporate proxies.
Embedded HTML	No build step. The UI is a template string in TypeScript.
XDG Base Directory	Respects `~/.local/state`, `~/.config`, `~/.cache` conventions.

The entire codebase uses only Node.js built-ins: node:fs, node:http, node:test, etc.

Roadmap

Phase	Status	What's Included
1	✅ Complete	Pipe capture, Web UI, Claude Skill, auto-redaction, `show` command
2	🚧 In Progress	`logifai exec npm run dev` — wrap commands, preserve colors and TTY
3	📋 Planned	SQLite FTS5 for millisecond full-text search across all sessions
4	💭 Exploring	MCP server protocol, semantic search, anomaly detection

Get Started in 60 Seconds

# 1. Install logifai
curl -fsSL https://raw.githubusercontent.com/fujitatomoya/logifai/main/install.sh | bash

# 2. Capture your dev server
npm run dev 2>&1 | logifai

# 3. Open the Web UI
# → http://localhost:3100

# 4. Install Claude Code integration
logifai install-skill

# 5. Ask Claude about your logs
# → "What errors happened in my last session?"

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