diff --git a/scripts/bootstrapper.py b/scripts/bootstrapper.py
new file mode 100644
index 0000000..9e5db34
--- /dev/null
+++ b/scripts/bootstrapper.py
@@ -0,0 +1,359 @@
+#!/usr/bin/env python3
+"""
+Bootstrapper — assemble pre-session context from knowledge store.
+
+Reads the knowledge store and produces a compact context block (2k tokens max)
+that can be injected into a new session so it starts with situational awareness.
+
+Usage:
+    python3 bootstrapper.py --repo the-nexus --agent mimo-sprint
+    python3 bootstrapper.py --repo timmy-home --global
+    python3 bootstrapper.py --global
+    python3 bootstrapper.py --repo the-nexus --max-tokens 1000
+"""
+
+import argparse
+import json
+import sys
+from pathlib import Path
+from typing import Optional
+
+# Resolve knowledge root relative to this script's parent
+SCRIPT_DIR = Path(__file__).resolve().parent
+REPO_ROOT = SCRIPT_DIR.parent
+KNOWLEDGE_DIR = REPO_ROOT / "knowledge"
+INDEX_PATH = KNOWLEDGE_DIR / "index.json"
+
+# Approximate token count: ~4 chars per token for English text
+CHARS_PER_TOKEN = 4
+
+# Category sort priority (lower = shown first)
+CATEGORY_PRIORITY = {
+    "pitfall": 0,
+    "tool-quirk": 1,
+    "pattern": 2,
+    "fact": 3,
+    "question": 4,
+}
+
+
+def load_index(index_path: Path = INDEX_PATH) -> dict:
+    """Load and validate the knowledge index."""
+    if not index_path.exists():
+        return {"version": 1, "total_facts": 0, "facts": []}
+
+    with open(index_path) as f:
+        data = json.load(f)
+
+    if "facts" not in data:
+        print(f"WARNING: index.json missing 'facts' key", file=sys.stderr)
+        return {"version": 1, "total_facts": 0, "facts": []}
+
+    return data
+
+
+def filter_facts(
+    facts: list[dict],
+    repo: Optional[str] = None,
+    agent: Optional[str] = None,
+    include_global: bool = True,
+) -> list[dict]:
+    """Filter facts by repo, agent, and global scope."""
+    filtered = []
+
+    for fact in facts:
+        fact_repo = fact.get("repo", "global")
+        fact_agent = fact.get("agent", "")
+
+        # Match by repo (regardless of agent)
+        if repo and fact_repo == repo:
+            filtered.append(fact)
+            continue
+
+        # Match by exact agent type
+        if agent and fact_agent == agent:
+            filtered.append(fact)
+            continue
+
+        # Include global facts without agent restriction (universal facts)
+        if include_global and fact_repo == "global" and not fact_agent:
+            filtered.append(fact)
+
+    return filtered
+
+
+def sort_facts(facts: list[dict]) -> list[dict]:
+    """
+    Sort facts by: confidence (desc), then category priority, then fact text.
+    Most reliable and most dangerous facts come first.
+    """
+
+    def sort_key(f):
+        confidence = f.get("confidence", 0.5)
+        category = f.get("category", "fact")
+        cat_priority = CATEGORY_PRIORITY.get(category, 5)
+        return (-confidence, cat_priority, f.get("fact", ""))
+
+    return sorted(facts, key=sort_key)
+
+
+def load_repo_knowledge(repo: str) -> Optional[str]:
+    """Load per-repo knowledge markdown if it exists."""
+    repo_path = KNOWLEDGE_DIR / "repos" / f"{repo}.md"
+    if repo_path.exists():
+        return repo_path.read_text().strip()
+    return None
+
+
+def load_agent_knowledge(agent: str) -> Optional[str]:
+    """Load per-agent knowledge markdown if it exists."""
+    agent_path = KNOWLEDGE_DIR / "agents" / f"{agent}.md"
+    if agent_path.exists():
+        return agent_path.read_text().strip()
+    return None
+
+
+def load_global_knowledge() -> list[str]:
+    """Load all global knowledge markdown files."""
+    global_dir = KNOWLEDGE_DIR / "global"
+    if not global_dir.exists():
+        return []
+
+    chunks = []
+    for md_file in sorted(global_dir.glob("*.md")):
+        content = md_file.read_text().strip()
+        if content:
+            chunks.append(content)
+    return chunks
+
+
+def render_facts_section(facts: list[dict], category: str, label: str) -> str:
+    """Render a section of facts for a single category."""
+    cat_facts = [f for f in facts if f.get("category") == category]
+    if not cat_facts:
+        return ""
+
+    lines = [f"### {label}\n"]
+    for f in cat_facts:
+        conf = f.get("confidence", 0.5)
+        fact_text = f.get("fact", "")
+        repo_tag = f.get("repo", "")
+        if repo_tag and repo_tag != "global":
+            lines.append(f"- [{conf:.0%}] ({repo_tag}) {fact_text}")
+        else:
+            lines.append(f"- [{conf:.0%}] {fact_text}")
+
+    return "\n".join(lines) + "\n"
+
+
+def estimate_tokens(text: str) -> int:
+    """Rough token estimate."""
+    return len(text) // CHARS_PER_TOKEN
+
+
+def truncate_to_tokens(text: str, max_tokens: int) -> str:
+    """Truncate text to approximately max_tokens, cutting at line boundaries."""
+    max_chars = max_tokens * CHARS_PER_TOKEN
+    if len(text) <= max_chars:
+        return text
+
+    # Cut at last newline before the limit
+    truncated = text[:max_chars]
+    last_newline = truncated.rfind("\n")
+    if last_newline > 0:
+        truncated = truncated[:last_newline]
+
+    return truncated + "\n\n[... truncated to fit context window ...]"
+
+
+def build_bootstrap_context(
+    repo: Optional[str] = None,
+    agent: Optional[str] = None,
+    include_global: bool = True,
+    max_tokens: int = 2000,
+    index_path: Path = INDEX_PATH,
+) -> str:
+    """
+    Build the full bootstrap context block.
+
+    Returns a markdown string suitable for injection into a session prompt.
+    """
+    index = load_index(index_path)
+    facts = index.get("facts", [])
+
+    # Filter
+    filtered = filter_facts(facts, repo=repo, agent=agent, include_global=include_global)
+
+    # Sort
+    sorted_facts = sort_facts(filtered)
+
+    # Build sections
+    sections = ["## What You Know (bootstrapped)\n"]
+
+    # Per-repo markdown knowledge
+    if repo:
+        repo_md = load_repo_knowledge(repo)
+        if repo_md:
+            sections.append(f"### Repo Notes: {repo}\n")
+            sections.append(repo_md + "\n")
+
+    # Structured facts by category
+    if sorted_facts:
+        # Group by source
+        repo_facts = [f for f in sorted_facts if f.get("repo") == repo] if repo else []
+        global_facts = [f for f in sorted_facts if f.get("repo") == "global"]
+        agent_facts = [f for f in sorted_facts if f.get("agent") == agent] if agent else []
+
+        if repo_facts:
+            sections.append(f"### Repo: {repo}\n")
+            for cat, label in [
+                ("pitfall", "PITFALLS"),
+                ("tool-quirk", "QUIRKS"),
+                ("pattern", "PATTERNS"),
+                ("fact", "FACTS"),
+                ("question", "OPEN QUESTIONS"),
+            ]:
+                section = render_facts_section(repo_facts, cat, label)
+                if section:
+                    sections.append(section)
+
+        if global_facts:
+            sections.append("### Global\n")
+            for cat, label in [
+                ("pitfall", "PITFALLS"),
+                ("tool-quirk", "QUIRKS"),
+                ("pattern", "PATTERNS"),
+                ("fact", "FACTS"),
+            ]:
+                section = render_facts_section(global_facts, cat, label)
+                if section:
+                    sections.append(section)
+
+        if agent_facts:
+            sections.append(f"### Agent Notes ({agent})\n")
+            for cat, label in [
+                ("pitfall", "PITFALLS"),
+                ("tool-quirk", "QUIRKS"),
+                ("pattern", "PATTERNS"),
+                ("fact", "FACTS"),
+            ]:
+                section = render_facts_section(agent_facts, cat, label)
+                if section:
+                    sections.append(section)
+
+    # Per-agent markdown knowledge
+    if agent:
+        agent_md = load_agent_knowledge(agent)
+        if agent_md:
+            sections.append(f"### Agent Profile: {agent}\n")
+            sections.append(agent_md + "\n")
+
+    # Global markdown knowledge
+    global_chunks = load_global_knowledge()
+    if global_chunks:
+        sections.append("### Global Notes\n")
+        sections.extend(chunk + "\n" for chunk in global_chunks)
+
+    # If nothing was found
+    if len(sections) == 1:
+        sections.append("_No relevant knowledge found. Starting fresh._\n")
+        if not facts:
+            sections.append(
+                "_Knowledge store is empty. Run the harvester to populate it._\n"
+            )
+
+    # Join and truncate
+    context = "\n".join(sections)
+    context = truncate_to_tokens(context, max_tokens)
+
+    return context
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="Assemble pre-session context from knowledge store"
+    )
+    parser.add_argument(
+        "--repo",
+        type=str,
+        default=None,
+        help="Repository name to filter facts by",
+    )
+    parser.add_argument(
+        "--agent",
+        type=str,
+        default=None,
+        help="Agent type to filter facts by (e.g., mimo-sprint, groq-fast)",
+    )
+    parser.add_argument(
+        "--global",
+        dest="include_global",
+        action="store_true",
+        default=True,
+        help="Include global facts (default: true)",
+    )
+    parser.add_argument(
+        "--no-global",
+        dest="include_global",
+        action="store_false",
+        help="Exclude global facts",
+    )
+    parser.add_argument(
+        "--max-tokens",
+        type=int,
+        default=2000,
+        help="Maximum token count for output (default: 2000)",
+    )
+    parser.add_argument(
+        "--index",
+        type=str,
+        default=None,
+        help="Path to index.json (default: knowledge/index.json)",
+    )
+    parser.add_argument(
+        "--json",
+        dest="output_json",
+        action="store_true",
+        help="Output raw JSON instead of markdown",
+    )
+
+    args = parser.parse_args()
+
+    index_path = Path(args.index) if args.index else INDEX_PATH
+
+    if args.output_json:
+        # JSON mode: return the filtered, sorted facts
+        index = load_index(index_path)
+        facts = index.get("facts", [])
+        filtered = filter_facts(
+            facts,
+            repo=args.repo,
+            agent=args.agent,
+            include_global=args.include_global,
+        )
+        sorted_facts = sort_facts(filtered)
+        output = {
+            "repo": args.repo,
+            "agent": args.agent,
+            "include_global": args.include_global,
+            "total_indexed": len(facts),
+            "matched": len(sorted_facts),
+            "facts": sorted_facts,
+        }
+        print(json.dumps(output, indent=2))
+    else:
+        # Markdown mode: full bootstrap context
+        context = build_bootstrap_context(
+            repo=args.repo,
+            agent=args.agent,
+            include_global=args.include_global,
+            max_tokens=args.max_tokens,
+            index_path=index_path,
+        )
+        print(context)
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/scripts/test_bootstrapper.py b/scripts/test_bootstrapper.py
new file mode 100644
index 0000000..e13d8b9
--- /dev/null
+++ b/scripts/test_bootstrapper.py
@@ -0,0 +1,239 @@
+#!/usr/bin/env python3
+"""
+Tests for bootstrapper.py — context assembly from knowledge store.
+"""
+
+import json
+import sys
+import tempfile
+from pathlib import Path
+
+# Add scripts dir to path for import
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+
+from bootstrapper import (
+    build_bootstrap_context,
+    estimate_tokens,
+    filter_facts,
+    load_index,
+    sort_facts,
+    truncate_to_tokens,
+)
+
+
+def make_index(facts: list[dict], tmp_dir: Path) -> Path:
+    """Create a temporary index.json with given facts."""
+    index = {
+        "version": 1,
+        "last_updated": "2026-04-13T20:00:00Z",
+        "total_facts": len(facts),
+        "facts": facts,
+    }
+    path = tmp_dir / "index.json"
+    with open(path, "w") as f:
+        json.dump(index, f)
+    return path
+
+
+def test_empty_index():
+    """Empty knowledge store produces graceful output."""
+    with tempfile.TemporaryDirectory() as tmp:
+        tmp_dir = Path(tmp)
+        index_path = make_index([], tmp_dir)
+
+        # Create empty knowledge dirs
+        for sub in ["repos", "agents", "global"]:
+            (tmp_dir / sub).mkdir(exist_ok=True)
+
+        context = build_bootstrap_context(
+            repo="the-nexus", index_path=index_path
+        )
+        assert "No relevant knowledge found" in context
+        assert "Starting fresh" in context
+        print("PASS: empty_index")
+
+
+def test_filter_by_repo():
+    """Filter facts by repository."""
+    facts = [
+        {"fact": "A", "category": "fact", "repo": "the-nexus", "confidence": 0.9},
+        {"fact": "B", "category": "fact", "repo": "fleet-ops", "confidence": 0.8},
+        {"fact": "C", "category": "fact", "repo": "global", "confidence": 0.7},
+    ]
+    filtered = filter_facts(facts, repo="the-nexus", include_global=True)
+    texts = [f["fact"] for f in filtered]
+    assert "A" in texts
+    assert "B" not in texts
+    assert "C" in texts
+    print("PASS: filter_by_repo")
+
+
+def test_filter_by_agent():
+    """Filter facts by agent type."""
+    facts = [
+        {"fact": "A", "category": "pattern", "repo": "global", "agent": "mimo-sprint", "confidence": 0.8},
+        {"fact": "B", "category": "pattern", "repo": "global", "agent": "groq-fast", "confidence": 0.7},
+        {"fact": "C", "category": "fact", "repo": "global", "confidence": 0.9},
+    ]
+    filtered = filter_facts(facts, agent="mimo-sprint", include_global=True)
+    texts = [f["fact"] for f in filtered]
+    assert "A" in texts
+    assert "B" not in texts
+    assert "C" in texts  # global, no agent restriction
+    print("PASS: filter_by_agent")
+
+
+def test_no_global_flag():
+    """Excluding global facts works."""
+    facts = [
+        {"fact": "A", "category": "fact", "repo": "the-nexus", "confidence": 0.9},
+        {"fact": "B", "category": "fact", "repo": "global", "confidence": 0.8},
+    ]
+    filtered = filter_facts(facts, repo="the-nexus", include_global=False)
+    texts = [f["fact"] for f in filtered]
+    assert "A" in texts
+    assert "B" not in texts
+    print("PASS: no_global_flag")
+
+
+def test_sort_by_confidence():
+    """Facts sort by confidence descending."""
+    facts = [
+        {"fact": "low", "category": "fact", "repo": "global", "confidence": 0.3},
+        {"fact": "high", "category": "fact", "repo": "global", "confidence": 0.95},
+        {"fact": "mid", "category": "fact", "repo": "global", "confidence": 0.7},
+    ]
+    sorted_f = sort_facts(facts)
+    assert sorted_f[0]["fact"] == "high"
+    assert sorted_f[1]["fact"] == "mid"
+    assert sorted_f[2]["fact"] == "low"
+    print("PASS: sort_by_confidence")
+
+
+def test_sort_pitfalls_first():
+    """Pitfalls sort before facts at same confidence."""
+    facts = [
+        {"fact": "regular fact", "category": "fact", "repo": "global", "confidence": 0.8},
+        {"fact": "danger pitfall", "category": "pitfall", "repo": "global", "confidence": 0.8},
+    ]
+    sorted_f = sort_facts(facts)
+    assert sorted_f[0]["category"] == "pitfall"
+    print("PASS: sort_pitfalls_first")
+
+
+def test_truncate_to_tokens():
+    """Truncation cuts at line boundary."""
+    text = "line1\nline2\nline3\nline4\nline5\n"
+    truncated = truncate_to_tokens(text, max_tokens=2)  # ~8 chars
+    assert "line1" in truncated
+    assert "truncated" in truncated.lower()
+    print("PASS: truncate_to_tokens")
+
+
+def test_estimate_tokens():
+    """Token estimation is reasonable."""
+    text = "a" * 400
+    tokens = estimate_tokens(text)
+    assert 90 <= tokens <= 110  # ~100 tokens
+    print("PASS: estimate_tokens")
+
+
+def test_build_full_context():
+    """Full context with facts renders correctly."""
+    facts = [
+        {"fact": "API merges fail with 405", "category": "pitfall", "repo": "the-nexus", "confidence": 0.95},
+        {"fact": "Has 50+ open PRs", "category": "fact", "repo": "the-nexus", "confidence": 0.9},
+        {"fact": "Token at ~/.config/gitea/token", "category": "tool-quirk", "repo": "global", "confidence": 0.9},
+        {"fact": "Check git remote -v first", "category": "pattern", "repo": "global", "confidence": 0.8},
+    ]
+
+    with tempfile.TemporaryDirectory() as tmp:
+        tmp_dir = Path(tmp)
+        index_path = make_index(facts, tmp_dir)
+
+        # Create knowledge dirs
+        for sub in ["repos", "agents", "global"]:
+            (tmp_dir / sub).mkdir(exist_ok=True)
+
+        context = build_bootstrap_context(
+            repo="the-nexus",
+            agent="mimo-sprint",
+            include_global=True,
+            index_path=index_path,
+        )
+
+        assert "What You Know" in context
+        assert "PITFALLS" in context
+        assert "API merges fail with 405" in context
+        assert "the-nexus" in context
+        assert "Token at" in context  # global fact included
+        print("PASS: build_full_context")
+
+
+def test_max_tokens_respected():
+    """Output respects max_tokens limit."""
+    # Generate lots of facts
+    facts = [
+        {"fact": f"Fact number {i} with some detail about things", "category": "fact", "repo": "global", "confidence": 0.8}
+        for i in range(100)
+    ]
+
+    with tempfile.TemporaryDirectory() as tmp:
+        tmp_dir = Path(tmp)
+        index_path = make_index(facts, tmp_dir)
+        for sub in ["repos", "agents", "global"]:
+            (tmp_dir / sub).mkdir(exist_ok=True)
+
+        context = build_bootstrap_context(
+            repo=None,
+            max_tokens=500,
+            index_path=index_path,
+        )
+
+        actual_tokens = estimate_tokens(context)
+        # Allow 10% overshoot since we cut at line boundaries
+        assert actual_tokens <= 550, f"Expected ~500 tokens, got {actual_tokens}"
+        print(f"PASS: max_tokens_respected (got {actual_tokens} tokens)")
+
+
+def test_missing_index_graceful():
+    """Missing index.json doesn't crash."""
+    with tempfile.TemporaryDirectory() as tmp:
+        tmp_dir = Path(tmp)
+        # Don't create index.json
+        for sub in ["repos", "agents", "global"]:
+            (tmp_dir / sub).mkdir(exist_ok=True)
+
+        fake_index = tmp_dir / "nonexistent.json"
+        context = build_bootstrap_context(repo="anything", index_path=fake_index)
+        assert "No relevant knowledge found" in context
+        print("PASS: missing_index_graceful")
+
+
+if __name__ == "__main__":
+    tests = [
+        test_empty_index,
+        test_filter_by_repo,
+        test_filter_by_agent,
+        test_no_global_flag,
+        test_sort_by_confidence,
+        test_sort_pitfalls_first,
+        test_truncate_to_tokens,
+        test_estimate_tokens,
+        test_build_full_context,
+        test_max_tokens_respected,
+        test_missing_index_graceful,
+    ]
+
+    passed = 0
+    failed = 0
+    for test in tests:
+        try:
+            test()
+            passed += 1
+        except Exception as e:
+            print(f"FAIL: {test.__name__} — {e}")
+            failed += 1
+
+    print(f"\n{passed} passed, {failed} failed")
+    sys.exit(0 if failed == 0 else 1)
diff --git a/scripts/test_harvest_prompt.py b/scripts/test_harvest_prompt.py
index d3d3f51..fa6d61a 100644
--- a/scripts/test_harvest_prompt.py
+++ b/scripts/test_harvest_prompt.py
@@ -1,41 +1,129 @@
 #!/usr/bin/env python3
 """
-Test script for knowledge extraction prompt.
-Validates that the prompt produces consistent, structured output.
+Test harness for knowledge extraction prompt.
+Validates output structure, content quality, and hallucination resistance.
+
+Usage:
+    python3 scripts/test_harvest_prompt.py                    # Run all tests
+    python3 scripts/test_harvest_prompt.py --transcript FILE  # Test against a real transcript
+    python3 scripts/test_harvest_prompt.py --validate FILE    # Validate an existing extraction JSON
 """
 
 import json
 import sys
+import argparse
 from pathlib import Path
 
-def validate_knowledge_item(item):
-    """Validate a single knowledge item."""
-    required_fields = ["fact", "category", "repo", "confidence"]
-    for field in required_fields:
-        if field not in item:
-            return False, f"Missing field: {field}"
-    
-    if not isinstance(item["fact"], str) or len(item["fact"].strip()) == 0:
-        return False, "Fact must be a non-empty string"
-    
-    valid_categories = ["fact", "pitfall", "pattern", "tool-quirk", "question"]
-    if item["category"] not in valid_categories:
-        return False, f"Invalid category: {item['category']}"
-    
-    if not isinstance(item["repo"], str):
-        return False, "Repo must be a string"
-    
-    if not isinstance(item["confidence"], (int, float)):
-        return False, "Confidence must be a number"
-    
-    if not (0.0 <= item["confidence"] <= 1.0):
-        return False, "Confidence must be between 0.0 and 1.0"
-    
-    return True, "Valid"
+VALID_CATEGORIES = {"fact", "pitfall", "pattern", "tool-quirk", "question"}
+REQUIRED_FIELDS = {"fact", "category", "repo", "confidence", "evidence"}
+REQUIRED_META = {"session_outcome", "tools_used", "repos_touched", "error_count", "knowledge_count"}
 
-def test_sample_transcript():
-    """Test with a sample transcript."""
-    sample_transcript = """
+
+def validate_knowledge_item(item, idx):
+    """Validate a single knowledge item. Returns list of errors."""
+    errors = []
+    if not isinstance(item, dict):
+        return [f"Item {idx}: not a dict"]
+    for field in REQUIRED_FIELDS:
+        if field not in item:
+            errors.append(f"Item {idx}: missing field '{field}'")
+    if not isinstance(item.get("fact", ""), str) or len(item.get("fact", "").strip()) == 0:
+        errors.append(f"Item {idx}: fact must be a non-empty string")
+    if item.get("category") not in VALID_CATEGORIES:
+        errors.append(f"Item {idx}: invalid category '{item.get('category')}'")
+    if not isinstance(item.get("repo", ""), str) or len(item.get("repo", "").strip()) == 0:
+        errors.append(f"Item {idx}: repo must be a non-empty string")
+    conf = item.get("confidence")
+    if not isinstance(conf, (int, float)) or not (0.0 <= conf <= 1.0):
+        errors.append(f"Item {idx}: confidence must be a number 0.0-1.0, got {conf}")
+    if not isinstance(item.get("evidence", ""), str) or len(item.get("evidence", "").strip()) == 0:
+        errors.append(f"Item {idx}: evidence must be a non-empty string (hallucination check)")
+    return errors
+
+
+def validate_extraction(data):
+    """Validate a full extraction result. Returns (is_valid, errors, warnings)."""
+    errors = []
+    warnings = []
+
+    if not isinstance(data, dict):
+        return False, ["Root is not a JSON object"], []
+
+    if "knowledge" not in data:
+        return False, ["Missing 'knowledge' array"], []
+
+    if not isinstance(data["knowledge"], list):
+        return False, ["'knowledge' is not an array"], []
+
+    for i, item in enumerate(data["knowledge"]):
+        errors.extend(validate_knowledge_item(item, i))
+
+    # Meta block validation
+    if "meta" not in data:
+        warnings.append("Missing 'meta' block (session_outcome, tools_used, etc.)")
+    else:
+        meta = data["meta"]
+        for field in REQUIRED_META:
+            if field not in meta:
+                warnings.append(f"Meta missing field '{field}'")
+
+    # Quality checks
+    facts = data["knowledge"]
+    if len(facts) == 0:
+        warnings.append("No knowledge extracted (empty session or extraction failure)")
+
+    # Check for near-duplicate facts
+    seen_facts = set()
+    for item in facts:
+        normalized = item.get("fact", "").lower().strip()[:80]
+        if normalized in seen_facts:
+            warnings.append(f"Duplicate fact detected: '{normalized[:50]}...'")
+        seen_facts.add(normalized)
+
+    # Check confidence distribution
+    confidences = [item.get("confidence", 0) for item in facts]
+    if confidences:
+        avg_conf = sum(confidences) / len(confidences)
+        if avg_conf > 0.9:
+            warnings.append(f"Average confidence {avg_conf:.2f} is suspiciously high (possible hallucination)")
+        if avg_conf < 0.4:
+            warnings.append(f"Average confidence {avg_conf:.2f} is very low (extraction may be too cautious)")
+
+    return len(errors) == 0, errors, warnings
+
+
+def validate_transcript_coverage(data, transcript):
+    """
+    Check that extracted facts are actually supported by the transcript.
+    This is a heuristic — checks that key terms from facts appear in transcript.
+    Returns list of potential hallucinations.
+    """
+    hallucinations = []
+    transcript_lower = transcript.lower()
+
+    for item in data.get("knowledge", []):
+        fact = item.get("fact", "")
+        evidence = item.get("evidence", "")
+
+        # Check if evidence string appears in transcript
+        if evidence and evidence.lower() not in transcript_lower:
+            # Partial match — check if key terms are present
+            evidence_words = set(evidence.lower().split())
+            transcript_words = set(transcript_lower.split())
+            overlap = evidence_words & transcript_words
+            if len(overlap) < min(3, len(evidence_words) * 0.3):
+                hallucinations.append({
+                    "fact": fact[:80],
+                    "evidence": evidence[:80],
+                    "issue": "Evidence not found in transcript — possible hallucination"
+                })
+
+    return hallucinations
+
+
+# --- Test transcripts ---
+
+SAMPLE_TRANSCRIPT_SUCCESS = """
 User: Clone the repo at forge.alexanderwhitestone.com/Timmy_Foundation/compounding-intelligence
 Agent: Trying git clone... Error: 401 Unauthorized
 Agent: Checking for token... Found in ~/.config/gitea/token
@@ -44,30 +132,253 @@ Agent: Clone successful with token authentication
 Agent: Now examining the repo structure...
 Agent: Found knowledge/index.json with 0 facts
 Agent: Creating harvest-prompt.md in templates/
+Agent: Done. Files created: templates/harvest-prompt.md, scripts/test_harvest_prompt.py
 """
-    
-    # This would be replaced with actual prompt execution
-    print("Sample transcript processed")
-    print("Expected categories: fact, pitfall, pattern, tool-quirk, question")
-    return True
 
-if __name__ == "__main__":
-    print("Testing knowledge extraction prompt...")
-    
-    # Test 1: Validate prompt file exists
+SAMPLE_TRANSCRIPT_FAILURE = """
+User: Deploy the cron jobs to production
+Agent: Connecting to VPS... SSH timeout after 30s
+Agent: Retrying with verbose output... Connection refused on port 22
+Agent: Checking firewall rules... iptables shows port 22 is open
+Agent: Checking sshd config... sshd is not running
+Agent: Attempting to start sshd... systemctl start sshd failed: unit not found
+Agent: ERROR: OpenSSH server not installed on this VPS
+Agent: Cannot proceed without SSH access. Deployment blocked.
+"""
+
+SAMPLE_TRANSCRIPT_API_QUIRK = """
+User: List all open issues in hermes-agent
+Agent: Querying Gitea API... endpoint: /repos/Timmy_Foundation/hermes-agent/issues?state=open&limit=50
+Agent: Response: 0 items. That's odd.
+Agent: Trying without state filter... endpoint: /repos/Timmy_Foundation/hermes-agent/issues?limit=50
+Agent: Response: 50 items returned, but all have pull_request field. These are PRs, not issues.
+Agent: Gitea issues API returns PRs alongside issues. Must filter by presence of pull_request key.
+Agent: Also discovered: state=open parameter returns empty when used with limit=50, but works with limit=5.
+Agent: This appears to be a Gitea API quirk — pagination interacts with state filter unexpectedly.
+Agent: Workaround: fetch without state filter, then filter client-side for state=='open' and 'pull_request' not in item.
+"""
+
+
+def run_tests():
+    """Run the built-in test suite."""
+    tests_passed = 0
+    tests_failed = 0
+
+    print("=" * 60)
+    print("KNOWLEDGE EXTRACTION PROMPT — TEST SUITE")
+    print("=" * 60)
+
+    # Test 1: Prompt file exists and is under 2k tokens (~8k chars)
+    print("\n[Test 1] Prompt file size constraint")
     prompt_path = Path("templates/harvest-prompt.md")
     if not prompt_path.exists():
-        print("ERROR: harvest-prompt.md not found")
-        sys.exit(1)
-    
-    print(f"OK: Prompt file exists: {prompt_path}")
-    
-    # Test 2: Check prompt size
-    prompt_size = prompt_path.stat().st_size
-    print(f"OK: Prompt size: {prompt_size} bytes")
-    
-    # Test 3: Test sample transcript processing
-    if test_sample_transcript():
-        print("OK: Sample transcript test passed")
-    
-    print("\nAll tests passed!")
+        print("  FAIL: harvest-prompt.md not found")
+        tests_failed += 1
+    else:
+        size = prompt_path.stat().st_size
+        # Rough token estimate: ~4 chars per token
+        est_tokens = size / 4
+        print(f"  Prompt size: {size} bytes (~{est_tokens:.0f} tokens)")
+        if est_tokens > 2000:
+            print(f"  WARN: Prompt exceeds ~1500 tokens (target: ~1000)")
+        else:
+            print(f"  PASS: Within token budget")
+        tests_passed += 1
+
+    # Test 2: Validate a well-formed extraction
+    print("\n[Test 2] Valid extraction passes validation")
+    valid_extraction = {
+        "knowledge": [
+            {
+                "fact": "Gitea auth token is at ~/.config/gitea/token",
+                "category": "tool-quirk",
+                "repo": "global",
+                "confidence": 0.9,
+                "evidence": "Found in ~/.config/gitea/token"
+            },
+            {
+                "fact": "Clone fails with 401 when no token is provided",
+                "category": "pitfall",
+                "repo": "compounding-intelligence",
+                "confidence": 0.9,
+                "evidence": "Error: 401 Unauthorized"
+            }
+        ],
+        "meta": {
+            "session_outcome": "success",
+            "tools_used": ["git"],
+            "repos_touched": ["compounding-intelligence"],
+            "error_count": 1,
+            "knowledge_count": 2
+        }
+    }
+    is_valid, errors, warnings = validate_extraction(valid_extraction)
+    if is_valid:
+        print(f"  PASS: Valid extraction accepted ({len(warnings)} warnings)")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Valid extraction rejected: {errors}")
+        tests_failed += 1
+
+    # Test 3: Reject missing fields
+    print("\n[Test 3] Missing fields are rejected")
+    bad_extraction = {
+        "knowledge": [
+            {"fact": "Something learned", "category": "fact"}  # Missing repo, confidence, evidence
+        ]
+    }
+    is_valid, errors, warnings = validate_extraction(bad_extraction)
+    if not is_valid:
+        print(f"  PASS: Rejected with {len(errors)} errors")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Should have rejected missing fields")
+        tests_failed += 1
+
+    # Test 4: Reject invalid category
+    print("\n[Test 4] Invalid category is rejected")
+    bad_cat = {
+        "knowledge": [
+            {"fact": "Test", "category": "discovery", "repo": "x", "confidence": 0.8, "evidence": "test"}
+        ]
+    }
+    is_valid, errors, warnings = validate_extraction(bad_cat)
+    if not is_valid and any("category" in e for e in errors):
+        print(f"  PASS: Invalid category 'discovery' rejected")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Should have rejected invalid category")
+        tests_failed += 1
+
+    # Test 5: Detect near-duplicates
+    print("\n[Test 5] Duplicate detection")
+    dup_extraction = {
+        "knowledge": [
+            {"fact": "Token is at ~/.config/gitea/token", "category": "fact", "repo": "x", "confidence": 0.9, "evidence": "a"},
+            {"fact": "Token is at ~/.config/gitea/token", "category": "fact", "repo": "x", "confidence": 0.9, "evidence": "b"}
+        ],
+        "meta": {"session_outcome": "success", "tools_used": [], "repos_touched": [], "error_count": 0, "knowledge_count": 2}
+    }
+    is_valid, errors, warnings = validate_extraction(dup_extraction)
+    if any("Duplicate" in w for w in warnings):
+        print(f"  PASS: Duplicate detected")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Should have detected duplicate")
+        tests_failed += 1
+
+    # Test 6: Hallucination check against transcript
+    print("\n[Test 6] Hallucination detection")
+    hallucinated = {
+        "knowledge": [
+            {
+                "fact": "Database port is 5433",
+                "category": "fact",
+                "repo": "x",
+                "confidence": 0.9,
+                "evidence": "PostgreSQL listening on port 5433"
+            }
+        ],
+        "meta": {"session_outcome": "success", "tools_used": [], "repos_touched": [], "error_count": 0, "knowledge_count": 1}
+    }
+    hallucinations = validate_transcript_coverage(hallucinated, SAMPLE_TRANSCRIPT_SUCCESS)
+    if hallucinations:
+        print(f"  PASS: Hallucination detected ({len(hallucinations)} items)")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Should have detected hallucinated evidence")
+        tests_failed += 1
+
+    # Test 7: Failed session should extract pitfalls
+    print("\n[Test 7] Failed session extraction shape")
+    failed_extraction = {
+        "knowledge": [
+            {
+                "fact": "SSH server not installed on target VPS",
+                "category": "pitfall",
+                "repo": "global",
+                "confidence": 0.9,
+                "evidence": "ERROR: OpenSSH server not installed on this VPS"
+            },
+            {
+                "fact": "VPS blocks deployment without SSH access",
+                "category": "question",
+                "repo": "global",
+                "confidence": 0.7,
+                "evidence": "Cannot proceed without SSH access. Deployment blocked."
+            }
+        ],
+        "meta": {
+            "session_outcome": "failed",
+            "tools_used": ["ssh", "systemctl"],
+            "repos_touched": [],
+            "error_count": 3,
+            "knowledge_count": 2
+        }
+    }
+    is_valid, errors, warnings = validate_extraction(failed_extraction)
+    if is_valid:
+        categories = [item["category"] for item in failed_extraction["knowledge"]]
+        if "pitfall" in categories:
+            print(f"  PASS: Failed session extracted {len(categories)} items including pitfalls")
+            tests_passed += 1
+        else:
+            print(f"  FAIL: Failed session should extract pitfalls")
+            tests_failed += 1
+    else:
+        print(f"  FAIL: {errors}")
+        tests_failed += 1
+
+    # Test 8: Empty extraction is warned
+    print("\n[Test 8] Empty extraction warning")
+    empty = {"knowledge": [], "meta": {"session_outcome": "success", "tools_used": [], "repos_touched": [], "error_count": 0, "knowledge_count": 0}}
+    is_valid, errors, warnings = validate_extraction(empty)
+    if any("No knowledge" in w for w in warnings):
+        print(f"  PASS: Empty extraction warned")
+        tests_passed += 1
+    else:
+        print(f"  FAIL: Should warn on empty extraction")
+        tests_failed += 1
+
+    # Summary
+    print(f"\n{'=' * 60}")
+    print(f"Results: {tests_passed} passed, {tests_failed} failed")
+    print(f"{'=' * 60}")
+    return tests_failed == 0
+
+
+def validate_file(filepath):
+    """Validate an existing extraction JSON file."""
+    path = Path(filepath)
+    if not path.exists():
+        print(f"ERROR: {filepath} not found")
+        return False
+
+    data = json.loads(path.read_text())
+    is_valid, errors, warnings = validate_extraction(data)
+
+    print(f"Validation of {filepath}:")
+    print(f"  Knowledge items: {len(data.get('knowledge', []))}")
+    print(f"  Errors: {len(errors)}")
+    print(f"  Warnings: {len(warnings)}")
+
+    for e in errors:
+        print(f"  ERROR: {e}")
+    for w in warnings:
+        print(f"  WARN: {w}")
+
+    return is_valid
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Test knowledge extraction prompt")
+    parser.add_argument("--validate", help="Validate an existing extraction JSON file")
+    parser.add_argument("--transcript", help="Test against a real transcript file (informational)")
+    args = parser.parse_args()
+
+    if args.validate:
+        success = validate_file(args.validate)
+        sys.exit(0 if success else 1)
+    else:
+        success = run_tests()
+        sys.exit(0 if success else 1)
diff --git a/templates/harvest-prompt.md b/templates/harvest-prompt.md
index f423db9..32c6d20 100644
--- a/templates/harvest-prompt.md
+++ b/templates/harvest-prompt.md
@@ -2,98 +2,107 @@
 
 ## System Prompt
 
-You are a knowledge extraction engine. Your task is to analyze a session transcript and extract durable knowledge that will help future sessions be more efficient.
+You are a knowledge extraction engine. You read session transcripts and output ONLY structured JSON. You never infer. You never assume. You extract only what the transcript explicitly states.
 
-## Instructions
+## Prompt
 
-Read the session transcript carefully. Extract ONLY information that is explicitly stated in the transcript. Do NOT infer, assume, or hallucinate information.
-
-### Categories
-
-Extract knowledge into these categories:
-
-1. **fact**: Concrete, verifiable information learned (e.g., "Repository X has 5 files", "API returns JSON with field Y")
-2. **pitfall**: Errors encountered, wrong assumptions, things that wasted time (e.g., "Assumed API token was in env var GITEA_TOKEN, but it's in ~/.config/gitea/token")
-3. **pattern**: Successful sequences of actions (e.g., "To deploy: 1. Run tests 2. Build 3. Push to Gitea 4. Trigger webhook")
-4. **tool-quirk**: Environment-specific behaviors (e.g., "Token paths are different on macOS vs Linux", "URL format requires trailing slash")
-5. **question**: Things identified but not answered (e.g., "Need to determine optimal batch size for harvesting")
-
-### Output Format
-
-Return a JSON object with an array of extracted knowledge items. Each item must have:
-
-```json
-{
-  "fact": "One sentence description of the knowledge",
-  "category": "fact|pitfall|pattern|tool-quirk|question",
-  "repo": "Repository name this applies to, or 'global' if general",
-  "confidence": 0.0-1.0
-}
 ```
+TASK: Extract durable knowledge from this session transcript.
 
-### Confidence Scoring
+RULES:
+1. Extract ONLY information explicitly stated in the transcript.
+2. Do NOT infer, assume, or hallucinate.
+3. Every fact must be verifiable by pointing to a specific line in the transcript.
+4. If the session failed or was partial, extract pitfalls and questions — these are the most valuable.
+5. Be specific. "Gitea API is slow" is worthless. "Gitea issues endpoint with state=open returns empty when limit=50 but works with limit=5" is knowledge.
 
-- 0.9-1.0: Explicitly stated with verification (e.g., "Error message shows X")
-- 0.7-0.8: Clearly implied by multiple data points
-- 0.5-0.6: Suggested but not fully verified
-- 0.3-0.4: Inferred from limited data
-- 0.1-0.2: Speculative or uncertain
+CATEGORIES (assign exactly one per item):
+- fact: Concrete, verifiable thing learned (paths, formats, counts, configs)
+- pitfall: Error hit, wrong assumption, time wasted, thing that didn't work
+- pattern: Successful sequence that should be reused (deploy steps, debug flow)
+- tool-quirk: Environment-specific behavior (token paths, URL formats, API gotchas)
+- question: Something identified but not answered — the NEXT agent should investigate
 
-### Constraints
+CONFIDENCE:
+- 0.9: Directly observed with error output or explicit verification
+- 0.7: Multiple data points confirm, but not explicitly verified
+- 0.5: Suggested by context, not tested
+- 0.3: Inferred from limited evidence
 
-1. **No hallucination**: Only extract what's explicitly in the transcript
-2. **Specificity**: Each fact must be specific and actionable
-3. **Relevance**: Only extract knowledge that would help future sessions
-4. **Brevity**: One sentence per fact
-5. **Partial sessions**: Even failed or incomplete sessions may contain valuable pitfalls
-
-### Example Input/Output
-
-**Input Transcript (excerpt):**
-```
-User: Clone the repo at forge.alexanderwhitestone.com/Timmy_Foundation/compounding-intelligence
-Agent: Trying git clone... Error: 401 Unauthorized
-Agent: Checking for token... Found in ~/.config/gitea/token
-Agent: Token is gitea_token format, not OAuth
-Agent: Clone successful with token authentication
-```
-
-**Output:**
-```json
+OUTPUT FORMAT (valid JSON only, no markdown, no explanation):
 {
   "knowledge": [
     {
-      "fact": "Gitea repo at forge.alexanderwhitestone.com requires authentication for cloning",
-      "category": "fact",
-      "repo": "compounding-intelligence",
-      "confidence": 0.9
-    },
-    {
-      "fact": "Gitea authentication token is stored at ~/.config/gitea/token",
-      "category": "tool-quirk",
-      "repo": "global",
-      "confidence": 0.9
-    },
-    {
-      "fact": "Gitea uses gitea_token format, not OAuth for API access",
-      "category": "tool-quirk",
-      "repo": "global",
-      "confidence": 0.8
-    },
-    {
-      "fact": "Clone fails with 401 when no token is provided",
-      "category": "pitfall",
-      "repo": "compounding-intelligence",
-      "confidence": 0.9
+      "fact": "One specific sentence of knowledge",
+      "category": "fact|pitfall|pattern|tool-quirk|question",
+      "repo": "repo-name or global",
+      "confidence": 0.0-1.0,
+      "evidence": "Brief quote or reference from transcript that supports this"
     }
-  ]
+  ],
+  "meta": {
+    "session_outcome": "success|partial|failed",
+    "tools_used": ["tool1", "tool2"],
+    "repos_touched": ["repo1"],
+    "error_count": 0,
+    "knowledge_count": 0
+  }
 }
+
+TRANSCRIPT:
+{{transcript}}
 ```
 
-## Final Notes
+## Design Notes
 
-- Process the entire transcript, not just the beginning
-- Pay special attention to errors and corrections
-- Note any environment-specific details
-- Track tool-specific behaviors and quirks
-- If the session failed, focus on pitfalls and questions
+### Why this works with mimo-v2-pro
+
+Mimo needs:
+- Explicit format constraints ("valid JSON only, no markdown")
+- Clear category definitions with concrete examples
+- Hard rules before soft guidance
+- The transcript at the END (so it reads all instructions first)
+
+This prompt front-loads all rules, then gives the transcript last. Mimo follows the pattern.
+
+### Handling partial/failed sessions
+
+Failed sessions are the richest source of pitfalls. The prompt explicitly says:
+> "If the session failed or was partial, extract pitfalls and questions — these are the most valuable."
+
+This reframes failure as valuable output, not noise to discard.
+
+### The `evidence` field
+
+Added to the original spec. Every extracted item must cite where in the transcript it came from. This:
+- Prevents hallucination (can't cite what isn't there)
+- Enables verification (reviewer can check the source)
+- Trains confidence calibration (the agent must find evidence, not just claim it)
+
+### Token budget
+
+Target: ~1,000 tokens for the prompt (excluding transcript).
+
+```
+System prompt:        ~50 tokens
+Rules:               ~200 tokens
+Categories:          ~150 tokens
+Confidence:          ~100 tokens
+Output format:       ~200 tokens
+Design notes:        NOT included in prompt (documentation only)
+─────────────────────────────
+Total prompt:        ~700 tokens
+```
+
+Leaves ~300 tokens headroom for variable content (transcript insertion, edge cases).
+
+### What this replaces
+
+The v1 prompt had:
+- Verbose prose explanations (waste tokens for mimo)
+- No `evidence` field (hallucination risk)
+- No `meta` block (no session-level metadata)
+- No explicit handling of failed sessions
+- Example was too long (~150 tokens of example for a 1k prompt)
+
+This v2 is tighter, more structured, and adds the evidence requirement that prevents the #1 failure mode of extraction prompts: generating plausible-sounding facts that aren't in the transcript.