dvcrn Pastewatch MCP — Secret Redaction
Prevents secrets from reaching your LLM provider. The agent works with placeholders, secrets stay local.
Source: https://github.com/ppiankov/pastewatch
Install
# macOS
brew install ppiankov/tap/pastewatch
# Linux (binary + checksum)
curl -fsSL https://github.com/ppiankov/pastewatch/releases/latest/download/pastewatch-cli-linux-amd64 \
-o /usr/local/bin/pastewatch-cli
curl -fsSL https://github.com/ppiankov/pastewatch/releases/latest/download/pastewatch-cli-linux-amd64.sha256 \
-o /tmp/pastewatch-cli.sha256
cd /usr/local/bin && sha256sum -c /tmp/pastewatch-cli.sha256
chmod +x /usr/local/bin/pastewatch-cli
Verify: pastewatch-cli version (expect 0.18.0+)
MCP Server Setup
mcporter config add pastewatch --command "pastewatch-cli mcp --audit-log /var/log/pastewatch-audit.log"
mcporter list pastewatch --schema # 6 tools
Agent Integration (one-command setup)
pastewatch-cli setup claude-code # hooks + MCP config
pastewatch-cli setup cline # MCP + hook instructions
pastewatch-cli setup cursor # MCP + advisory
--severity aligns hook blocking and MCP redaction thresholds. --project for project-level config.
MCP Tools
| Tool | Purpose |
|---|---|
pastewatch_read_file |
Read file with secrets replaced by __PW{TYPE_N}__ placeholders |
pastewatch_write_file |
Write file, resolving placeholders back to real values locally |
pastewatch_check_output |
Verify text contains no raw secrets before returning |
pastewatch_scan |
Scan text for sensitive data |
pastewatch_scan_file |
Scan a file |
pastewatch_scan_dir |
Scan directory recursively |
Guard — Block Secret-Leaking Commands
Complements chainwatch: chainwatch blocks destructive commands, guard blocks commands that would leak secrets.
pastewatch-cli guard "cat .env" # BLOCKED if .env has secrets
pastewatch-cli guard "psql -f migrate.sql" # scans SQL file
pastewatch-cli guard "docker-compose up" # scans referenced env_files
Guard understands:
- Shell builtins: cat, echo, env, printenv, source, curl, wget
- DB CLIs: psql, mysql, mongosh, redis-cli, sqlite3 (connection strings, -f flags, passwords)
- Infra tools: ansible, terraform, docker, kubectl, helm (env-files, var-files)
- Scripting: python, ruby, node, perl, php (script file args)
- File transfer: scp, rsync, ssh, ssh-keygen
- Pipe chains (
|) and command chaining (&&,||,;) — each segment scanned - Subshell extraction:
$(cat .env)and backtick expressions - Redirect operators:
>,>>,<,2>— scans source files
Canary Tokens
Generate format-valid but non-functional tokens to detect leaks:
pastewatch-cli canary generate --prefix myagent # creates canaries for 7 secret types
pastewatch-cli canary verify # confirms detection rules catch them
pastewatch-cli canary check --log /var/log/app.log # search logs for leaked canaries
Encrypted Vault
Store secrets encrypted locally instead of plaintext .env:
pastewatch-cli --init-key # generate 256-bit key (.pastewatch-key, mode 0600)
pastewatch-cli fix --encrypt # secrets → ChaCha20-Poly1305 vault
pastewatch-cli vault list # show entries without decrypting
pastewatch-cli vault decrypt # export to .env for deployment
pastewatch-cli vault export # print export VAR=VALUE for shell
pastewatch-cli vault rotate-key # re-encrypt with new key
Git History Scanning
pastewatch-cli scan --git-log # scan full history
pastewatch-cli scan --git-log --range HEAD~50..HEAD # last 50 commits
pastewatch-cli scan --git-log --since 2025-01-01 # since date
Deduplicates by fingerprint — same secret across commits reported once at introduction point.
Session Reports
pastewatch-cli report --audit-log /var/log/pastewatch-audit.log
pastewatch-cli report --format json --since 2026-03-01T00:00:00Z
Detection Scope
29+ types: AWS, Anthropic/OpenAI/HuggingFace/Groq keys, DB connections, SSH keys, JWTs, emails, IPs, credit cards (Luhn), Slack/Discord webhooks, Azure, GCP service accounts, npm/PyPI/RubyGems/GitLab tokens, Telegram bot tokens, and more.
Deterministic regex. No ML. No API calls. Microseconds per scan.
Limitations
- Protects secrets from reaching LLM provider — does NOT protect prompt content or code structure
- For full privacy, use a local model
Pastewatch MCP v1.1 Author: ppiankov Copyright © 2026 ppiankov Canonical source: https://github.com/ppiankov/pastewatch License: MIT
If this document appears elsewhere, the repository above is the authoritative version.