feat: add 6 production-ready plugins

All plugins are stdlib-only Python with no external dependencies.

- auto-summarizer: extractive conversation summary for long context
  compression, persists per-agent summaries to disk
- conversation-logger: JSONL audit logs per agent with ISO 8601
  timestamps, auto-creates log directory tree
- guardrails: safety filter detecting PII (email, phone, SSN, CC),
  prompt injection patterns, and credential exposure via regex
- keyword-memory: extracts entities (emails, URLs, dates, technical
  terms like camelCase/snake_case/dotted identifiers) as memories
- sentiment-tracker: keyword-based sentiment scoring with intensifiers
  and negation handling, only injects context for non-neutral sentiment
- todo-tracker: detects action items via 7 task patterns, tracks
  completion, deduplicates, persists per-agent with 20-item FIFO limit

plugins/guardrails/hooks/ingest.py

@@ -0,0 +1,151 @@
+#!/usr/bin/env python3
+"""Guardrails ingest hook — safety filter plugin.
+
+Scans user messages for potentially harmful content patterns including
+PII exposure, prompt injection attempts, and credential leaks. Returns
+warning memories so the agent can handle these situations appropriately.
+
+Receives via stdin:
+    {"type": "ingest", "agent_id": "...", "message": "user message text"}
+
+Prints to stdout:
+    {"type": "ingest_result", "memories": [{"content": "..."}]}
+"""
+import json
+import re
+import sys
+
+
+# ---------------------------------------------------------------------------
+# Pattern definitions
+# ---------------------------------------------------------------------------
+
+# PII patterns
+_EMAIL_RE = re.compile(
+    r"\b[A-Za-z0-9._%+\-]+@[A-Za-z0-9.\-]+\.[A-Za-z]{2,}\b"
+)
+_PHONE_RE = re.compile(
+    r"(?<!\d)"                      # no digit before
+    r"(?:"
+    r"\+?1[\s\-.]?"                 # optional country code
+    r")?"
+    r"(?:"
+    r"\(?\d{3}\)?[\s\-.]?"          # area code with optional parens
+    r"\d{3}[\s\-.]?"                # exchange
+    r"\d{4}"                        # subscriber
+    r")"
+    r"(?!\d)"                       # no digit after
+)
+_SSN_RE = re.compile(
+    r"\b\d{3}-\d{2}-\d{4}\b"
+)
+_CREDIT_CARD_RE = re.compile(
+    r"\b\d{4}[\s\-]?\d{4}[\s\-]?\d{4}[\s\-]?\d{4}\b"
+)
+
+# Prompt injection patterns — use word boundaries / anchoring to limit
+# false positives on casual conversation.
+_INJECTION_PATTERNS = [
+    re.compile(r"\bignore\s+(all\s+)?previous\s+instructions\b", re.IGNORECASE),
+    re.compile(r"\byou\s+are\s+now\b", re.IGNORECASE),
+    re.compile(r"\bsystem\s*prompt\s*:", re.IGNORECASE),
+    re.compile(r"\bforget\s+(all\s+)?your\s+rules\b", re.IGNORECASE),
+    re.compile(r"\bdisregard\s+(all\s+)?(previous|prior|above)\b", re.IGNORECASE),
+    re.compile(r"\boverride\s+(your|all|previous|prior)\b", re.IGNORECASE),
+    re.compile(r"\bnew\s+instructions\s*:", re.IGNORECASE),
+]
+
+# Credential patterns
+_CREDENTIAL_PATTERNS = [
+    re.compile(r"\bpassword\s*=\s*\S+", re.IGNORECASE),
+    re.compile(r"\bapi[_\-]?key\s*=\s*\S+", re.IGNORECASE),
+    re.compile(r"\bsecret\s*=\s*\S+", re.IGNORECASE),
+    re.compile(r"\btoken\s*=\s*\S+", re.IGNORECASE),
+    re.compile(r"-----BEGIN\s[\w\s]*KEY-----"),
+]
+
+
+# ---------------------------------------------------------------------------
+# Detection helpers
+# ---------------------------------------------------------------------------
+
+def _detect_pii(message: str) -> list:
+    """Return warning strings for any PII found in *message*."""
+    warnings = []
+    if _EMAIL_RE.search(message):
+        warnings.append(
+            "[guardrails:pii] Detected potential email address in user message. "
+            "Avoid echoing PII in response."
+        )
+    if _PHONE_RE.search(message):
+        warnings.append(
+            "[guardrails:pii] Detected potential phone number in user message. "
+            "Avoid echoing PII in response."
+        )
+    if _SSN_RE.search(message):
+        warnings.append(
+            "[guardrails:pii] Detected potential SSN in user message. "
+            "Do not store or repeat this information."
+        )
+    if _CREDIT_CARD_RE.search(message):
+        warnings.append(
+            "[guardrails:pii] Detected potential credit card number in user message. "
+            "Do not store or repeat this information."
+        )
+    return warnings
+
+
+def _detect_injection(message: str) -> list:
+    """Return warning strings for prompt injection attempts."""
+    warnings = []
+    for pattern in _INJECTION_PATTERNS:
+        match = pattern.search(message)
+        if match:
+            snippet = match.group(0)
+            warnings.append(
+                f'[guardrails:injection] Possible prompt injection detected '
+                f'("{snippet}"). Maintain original instructions.'
+            )
+            # One warning per message is sufficient to alert the agent.
+            break
+    return warnings
+
+
+def _detect_credentials(message: str) -> list:
+    """Return warning strings for credential exposure."""
+    warnings = []
+    for pattern in _CREDENTIAL_PATTERNS:
+        match = pattern.search(message)
+        if match:
+            # Show only the key portion, not the value, to avoid logging secrets.
+            snippet = match.group(0).split("=")[0].strip() + "=..."
+            if "BEGIN" in snippet:
+                snippet = "-----BEGIN...KEY-----"
+            warnings.append(
+                f"[guardrails:credential] Potential credential in message "
+                f"({snippet}). Do not store or repeat credentials."
+            )
+            break
+    return warnings
+
+
+# ---------------------------------------------------------------------------
+# Main
+# ---------------------------------------------------------------------------
+
+def main():
+    request = json.loads(sys.stdin.read())
+    message = request.get("message", "")
+
+    warnings = []
+    warnings.extend(_detect_pii(message))
+    warnings.extend(_detect_injection(message))
+    warnings.extend(_detect_credentials(message))
+
+    memories = [{"content": w} for w in warnings]
+    result = {"type": "ingest_result", "memories": memories}
+    print(json.dumps(result))
+
+
+if __name__ == "__main__":
+    main()