Horizon MCP Server

Horizon Fidelity Monitor

"Quality is not a model property — it is a conversation property."

Horizon is a real-time conversation health monitor for AI agents. It tracks the structural dynamics of multi-turn conversations — semantic drift, information gain, ontological gap width, temporal desynchronisation, circadian cognitive load, conversation velocity, and causal reachability — dimensions that every LLM is architecturally blind to.

Based on the Trans-Horizon Communication Protocol (THCP) research. Three independent no-go theorems prove why no LLM can self-monitor these properties from the inside.

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Why this exists

Multi-turn AI agents lose accuracy. Our market research puts the number at 39% accuracy degradation after 5 turns — a structural property of conversations that standard observability tools (LangSmith, RAGAS, DeepEval) cannot see because they measure responses, not conversations.

Horizon was built to close that gap. In A/B experiments across four scenarios, adding Horizon monitoring produced +15.7% composite quality lift and 87% fewer hallucination events when Horizon events triggered interventions. The math is grounded in 173 academic references across information theory, cognitive science, category theory, and Lorentzian geometry.

• Read the demand proof → docs/research/market-demand.md
• Read the category argument → docs/content/naming-the-category-conversation-dynamics-monitoring.md
• Read the engineering case → docs/content/why-every-production-agent-needs-conversation-dynamics-monitoring.md

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Getting started

Three paths — pick the one that fits your workflow:

Path 1 — Hosted MCP (fastest, zero install)

The fastest way to add Horizon to any Cursor or Claude Desktop workspace. No Python required.

Request an alpha key → GitHub Discussions, then add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "horizon": {
      "url": "https://horizon.leocelis.com/sse",
      "headers": { "Authorization": "Bearer YOUR_KEY_HERE" }
    }
  }
}

In Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "horizon": {
      "url": "https://horizon.leocelis.com/sse",
      "headers": { "Authorization": "Bearer YOUR_KEY_HERE" }
    }
  }
}

That's it. Reload your MCP client and three tools appear: new_conversation, process_turn, configure_session.

Alpha access: Horizon's hosted endpoint is in private alpha. Keys are distributed to agent developers who want to monitor real projects. Open a GitHub Discussion to request one.

Path 2 — pip install (library integration)

pip install horizon-monitor

Verify your install (exercises the full pipeline on 5 canonical scenarios, ~25s):

horizon-validate

Path 3 — MCP server from source

pip install 'horizon-monitor[mcp]'
horizon serve                             # stdio — for Cursor, Claude Desktop
horizon serve --transport sse --port 3847 # SSE — for web/team deployments

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "horizon": { "command": "horizon", "args": ["serve"] }
  }
}

Full Cursor and Claude Desktop setup guides: docs/integrations/

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What it monitors

Standard observability tools evaluate individual response quality. Horizon evaluates conversation quality — a structurally different problem:

Horizon does not replace per-response quality tools. It adds the dimension they all lack.

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Quickstart

from horizon import FidelityMonitor
from datetime import datetime, timezone

monitor = FidelityMonitor()
session_id = monitor.new_conversation(metadata={"domain": "technical"})

result = monitor.process_turn(
    session_id,
    human_message="How does Python handle memory management?",
    agent_response="Python uses reference counting and a cyclic garbage collector...",
    timestamp=datetime.now(timezone.utc).isoformat(),
)

print(f"Fidelity:         {result.fidelity_score:.2f}")
print(f"Health:           {result.health_status}")
print(f"Circadian factor: {result.circadian_factor:.2f}")
print(f"Causal horizon:   {result.reachable_turns} reachable turns")
for event in result.events:
    print(f"  Event: {event.type} (confidence={event.confidence:.2f})")

---

Framework integrations

OpenAI SDK

from openai import OpenAI
from horizon import FidelityMonitor

monitor = FidelityMonitor()
session_id = monitor.new_conversation()
client = monitor.wrap(OpenAI(), session_id)

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Tell me about quantum computing."}]
)

traj = monitor.get_trajectory(session_id)
print(f"Fidelity: {traj.current_fidelity:.2f}  T*: {traj.estimated_t_star}")

monitor.wrap() accepts custom timestamp and context providers for testing and replay.

Anthropic SDK

from anthropic import Anthropic
from horizon import FidelityMonitor

monitor = FidelityMonitor()
session_id = monitor.new_conversation()
client = monitor.wrap(Anthropic(), session_id)

response = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Explain RLHF."}]
)

LangChain

from langchain_openai import ChatOpenAI
from horizon import FidelityMonitor
from horizon.integrations.langchain import HorizonCallback

monitor = FidelityMonitor()
session_id = monitor.new_conversation()
callback = HorizonCallback(monitor, session_id)

llm = ChatOpenAI(callbacks=[callback])
llm.invoke("Explain the CAP theorem.")
print(f"Fidelity: {callback.last_result.fidelity_score:.2f}")

OpenAI Agents SDK

from openai_agents import Agent, Runner
from horizon import FidelityMonitor

monitor = FidelityMonitor()
session_id = monitor.new_conversation()
agent = Agent(name="assistant", model="gpt-4o-mini", instructions="You are helpful.")

for user_message in conversation:
    result = Runner.run_sync(agent, user_message)
    monitor.process_turn(session_id, human_message=user_message,
        agent_response=result.final_output, timestamp=datetime.now(timezone.utc).isoformat())

---

4D Spacetime Signals

Every process_turn() returns a TurnResult with 29 fields across five signal families:

Core (always present)

Temporal (requires timestamp)

Pace (requires timestamp + turn ≥ 2)

Spacetime (requires timestamp + turn ≥ 2)

Causal (requires timestamp)

Spatial (requires client_context)

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14 Event Types

All events default to observe mode (emitted, not acted on). Enable active mode via configure() once your event achieves ≥ 0.7 precision/recall on your domain.

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Configure

# Per-session override
monitor.configure(
    session_id=session_id,
    clarification_threshold=0.25,           # tighter D_JS gate
    event_modes={"alert.drift": "active"},  # activate one event
)

# Compound weight override
monitor.configure(
    fidelity_weights={"alpha": 0.35, "lambda_r": 0.12, "lambda_i": 0.28, "beta": 0.25},
    temporal_weights={"gamma": 0.08, "delta": 0.04},
    spacetime_coefficients={"alpha": 1.0, "beta": 1.0, "gamma": 0.8, "delta_st": 0.5},
)

---

Export

# JSON
result = monitor.export_to(session_id, target="json")

# LangSmith / Langfuse / OpenTelemetry / Arize
result = monitor.export_to(session_id, target="langsmith",
    connection={"api_key": "ls__..."})

pip install horizon-monitor[langsmith]   # or langfuse, otel, arize

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Architecture

Input: plain strings (human_message, agent_response, optional timestamp, optional client_context)

Core pipeline (< 50ms on CPU):
  1. Embed both turns (local sentence-transformers, lazy-loaded)
  2–6.  IGT · D_JS · TWR · Bipredictability · Epsilon
  7. Temporal signals  — gap, retention, circadian, deictic
  8. Fidelity dynamics — composite score
  9. Health classification
 10. Pace signals       — velocity, acceleration
 11. Spacetime interval — ds² and interval class
 12. Causal reachability — light-cone membership
 13. Spatial signals    — device, location, frame shift
 14. Mode detection     — auto-classify conversation type
 15. Event evaluation   — 14 threshold checks
 16. Optional: SQLite persistence

Output: TurnResult dataclass (29 fields)

Design constraints (all test-enforced):

• Zero LLM calls — pure arithmetic and local embeddings
• Zero external network calls by default — fully local
• Zero transitive framework dependencies in core
• < 50ms core pipeline on CPU
• < 100MB memory for 100-turn conversations
• All events observe-by-default — never interferes unless explicitly configured

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Validation

All four IVD validation gates pass on a 5,602-record labelled corpus:

Cross-embedding stability: ρ_conv spread 0.026, ρ_turn spread 0.018 across three sentence-transformer backends (22M / 33M / 110M params). The fidelity signal lives in conversational structure, not in the embedding manifold.

Full evidence pack: docs/reviews/V0_2_0_EVIDENCE.md

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Deployment

Self-hosted Docker (MCP server on port 3847)

cd deploy/docker
docker compose up

Horizon serves the MCP API via SSE. Point .cursor/mcp.json to http://localhost:3847/sse. The Dockerfile pre-caches the all-MiniLM-L6-v2 weights at build time — zero cold start.

Hosted (DigitalOcean App Platform)

The official hosted endpoint is live at https://horizon.leocelis.com. It runs on DigitalOcean App Platform (single instance, Redis-backed session resumability) and requires a Bearer token. See Path 1 above.

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Development

git clone https://github.com/leocelis/horizon.git
cd horizon
python -m venv .venv && source .venv/bin/activate
pip install -e ".[dev]"

pytest tests/ -v                         # full suite
pytest tests/unit tests/integration tests/e2e -v   # fast path (~6 min)
ruff check src/ tests/
black --check src/ tests/

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Repository layout

horizon/
├── src/horizon/         # package source (PEP 517/518 src/ layout)
│   ├── engines/         # IGT, D_JS, TWR, coherence, fidelity, epsilon, mode
│   ├── spacetime/       # temporal, circadian, deictic, velocity, interval, light cone, spatial
│   ├── events/          # 14-event evaluator
│   ├── integrations/    # OpenAI, Anthropic, LangChain, export targets
│   ├── mcp/             # MCP server + CLI
│   └── storage/         # optional SQLite persistence
├── tests/               # unit / integration / e2e / perf / validation
├── examples/            # runnable framework demos
├── deploy/              # Procfile, build.sh, runtime.txt, docker/
├── docs/
│   ├── research/        # market-demand.md + THCP theoretical framework
│   ├── content/         # published pieces on conversation dynamics monitoring
│   ├── integrations/    # Cursor / Claude Desktop / Copilot setup guides
│   ├── spec/            # HORIZON_TECH_SPEC.md + intent.yaml
│   └── reviews/         # E2E reviews, validation evidence
└── pyproject.toml

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Background

Horizon is grounded in the Trans-Horizon Communication Protocol (THCP), a theoretical framework for human–AI communication. Five conjectures establish:

• THCP-1 — Irreducible ontological loss ε > 0 in every domain
• THCP-2 — An optimal conversation length T* exists beyond which fidelity decays
• THCP-3 — Communication requires encode/decode adjunction (bipredictability)
• THCP-4 — Global coherence requires sheaf gluing across all turns
• THCP-5 — Optimal trajectories lie on or near the conversation light cone

The monitor instruments all five conjectures as computable signals.

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Community

• Questions, use cases, alpha access: GitHub Discussions
• Bug reports and feature requests: GitHub Issues
• Contributing: CONTRIBUTING.md

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License

MIT — see LICENSE.