# Ctxfw – In-memory Tree-sitter AST compactor that cuts coding tokens by 72% > Source: > Published: 2026-09-22 16:34:42+00:00 **The deterministic boundary between probabilistic LLM hallucination and production infrastructure.** [Installation](#installation) • [Benchmarks](#ast-pruning-benchmarks) • [Diagnostic](#system-diagnostics) • [Architecture](#architecture) • [Enterprise Governance](#enterprise-governance) Autonomous coding agents (Claude, Gemini, Cursor, Antigravity) consume massive context windows with bloated peripheral dependencies, triggering token exhaustion, context drift, and security degradation. **CTXFW** is an open-core context firewall and Model Context Protocol (MCP) gatekeeper. It combines an **in-memory polyglot AST pruner** with a **deterministic axiomatic intake sieve**: 1. **Compacts Peripheral Code (72.4% token reduction)** : Replaces distance-1 and distance-2+ module implementations with clean interface signatures, type definitions, and functional stubs. 2. **Enforces Axiomatic Integrity (ACI** : Rejects ungrounded or deficient architecture briefs missing negative invariants ($\ge$ 0.9000)$N \ge 5$ ), bounded variable domains, deterministic state machines, or formal error taxonomies. 3. **Zero Telemetry Egress** : Guaranteed local execution with zero network telemetry leakage on standard operating mode. CTXFW operates directly at the syntax tree layer using native polyglot grammars: | Benchmark Dimension | Raw Context Ingestion | CTXFW Topological Compactor | Performance Gain / Impact | |---|---|---|---| | **Token Consumption** | 100% (Raw Files) | 27.6% (Interface Stubs) | **72.4% Bloat Eliminated** | | **Engine Compaction Overhead** | — | Native in-memory parser | **< 5.0 ms** | | **Warm Cache Hit Overhead** | — | SQLite WAL semantic cache | **< 0.8 ms** | | **Stdio Telemetry Egress** | Unsanitized stdout | Pure isolated JSON-RPC | **Zero Egress (100% Isolated)** | | **Axiom Verification Latency** | — | Sieve evaluation | **< 12.0 ms** | | **CI/CD Pre-Commit Latency** | — | Headless git sentry | **< 85.0 ms** | Empirical context reduction metrics generated via `ctxfw.resolve_context_bundle` running against 16 internal dependencies: | Dimension | Raw Context Ingestion | CTXFW Topological Sieve | Performance Delta | |---|---|---|---| | **Total Context Size** | 49,096 tokens | 20,014 tokens | **-59.5% Net Reduction** | | **Tokens Eliminated** | 0 tokens | 29,222 tokens | **29,222 bloat tokens pruned** | | **Transitive Deps (** | 7,275 tokens | 4,763 tokens | **Up to 91.9% reduction** | | **FinOps Cost Impact** | Base Cost | Reduced by $0.0877 USD / prompt | **~$87.70 USD saved per 1K calls** | | **AST Compaction Latency** | — | 1,407.96 ms | In-memory Tree-Sitter parsing | | **Attestation Integrity** | None | SHA-256 sealed | Strict interface preservation | **Topological Hierarchy Breakdown:** - **`ctxfw/cli.py`)** : 100% Full Implementation preserved.$D_0$ Target ( - **`gatekeeper.py`, `mcp.py`)** : Implementation truncated to typed stubs ($D_1$ Direct Deps (e.g.`...` ). Token savings:**73% – 86%** . - **`polyglot.py`)** : Nominal symbols only. Token savings:$D_{2+}$ Transitive Deps (e.g.**91.9%** . Install via `pip` or isolated environment manager: ``` pip install ctxfw ``` Or for global CLI availability using `pipx`: ``` pipx install ctxfw ``` Register the stdio server directly in your IDE or client configuration (`claude_desktop_config.json`, Cursor, Windsurf, or Antigravity): ``` { "mcpServers": { "ctxfw": { "command": "ctxfw", "args": ["mcp"] } } } ``` CTXFW is indexed and verified with Grade A compliance on the official Glama MCP registry: Direct access to tool inspection, schemas, and live diagnostic telemetry on [Glama](https://glama.ai/mcp/servers/heuristicolab/ctxfw). Validate local environment readiness, stdio isolation purity, SQLite WAL concurrency, and Tree-Sitter grammars with a single command: ``` ctxfw doctor ======================================================================== CTXFW DOCTOR // HIGH-ASSURANCE HEALTH & ISOLATION DIAGNOSTIC ======================================================================== [PASS] Python Package & sys.path ctxfw v3.5.0 loaded cleanly. [PASS] MCP stdio Stream Isolation 100% pure JSON-RPC on stdout. Diagnostic logs isolated to stderr. [PASS] Global CLI Executable (PATH) Binary 'ctxfw' found in PATH. [PASS] Axiomatic Sieve Engine Evaluation verified (ACI: 1.0000, Invariants: 5). [PASS] SQLite WAL Cache & Concurrency Journal mode: WAL, Busy timeout: 5000ms. [PASS] Polyglot Tree-Sitter Grammars Initialized language parsers (typescript, go, java). ------------------------------------------------------------------------ Overall Verdict: [HEALTHY] [ATTESTED] Perimeter defense operational. ======================================================================== CTXFW // 72.4% AST Bloat Eliminated. Zero Telemetry Egress. Need team-wide budget circuit breakers or multi-node proxy governance? Control Plane & Enterprise Licensing: https://ctxfw.heuristicolab.com ======================================================================== ``` CTXFW enforces a strict deterministic perimeter dividing probabilistic agent code from the core codebase: ``` PROBABILISTIC DOMAIN DETERMINISTIC PERIMETER ┌───────────────────────┐ ┌────────────────────────────────────────┐ │ Autonomous AI Agent │ │ CTXFW ENGINE │ │ (Claude / Gemini / │ │ │ │ Cursor / Antigravity│ │ ┌──────────────────────────────────┐ │ └───────────┬───────────┘ │ │ Polyglot AST Topological Engine│ │ │ │ │ - Python (ast) │ │ │ Target Context / Brief │ │ - TypeScript / Go / Java (CST) │ │ ▼ │ │ - Multi-Depth Interface Stubs │ │ ┌───────────────────────┐ │ └────────────────┬─────────────────┘ │ │ MCP Stdio Interceptor ├─────────────────►│ │ │ └───────────────────────┘ │ ┌────────────────┴─────────────────┐ │ │ │ SQLite WAL High-Concurrency │ │ │ │ Semantic Cache (<5ms warm hit) │ │ │ └────────────────┬─────────────────┘ │ │ ▼ │ │ [ ACI >= 0.9000? ] │ │ / \ │ │ YES NO │ │ │ │ │ │ ▼ ▼ │ │ ┌──────────────┐ ┌─────────────────┐ │ │ │ VERIFIED │ │ QUARANTINED │ │ │ │ SHA-256 Seal │ │ Execution Halt │ │ │ └──────┬───────┘ └────────┬────────┘ │ └────────┼────────────────────┼──────────┘ │ │ ▼ ▼ [ Code Generation ] [ Forensic Report ] [ & Git Permitted ] [ Pre-Commit Abort] ``` 1. **Polyglot Tree-Sitter Pruner** : - Compiles topological dependency trees. Distance 0 (target file) is preserved in full; Distance 1 dependencies retain signatures and docstrings while pruning implementation logic; Distance 2+ dependencies are reduced to compact type stubs. - Built-in support for **Python** ,**TypeScript/JavaScript** ,**Go** , and**Java** . 2. **SQLite WAL High-Concurrency Semantic Cache** : - Atomic multi-process caching configured with Write-Ahead Logging (`PRAGMA journal_mode=WAL` ) and`busy_timeout=5000ms` , delivering sub-millisecond warm cache hits. 3. Atomic multi-process caching configured with Write-Ahead Logging ( 4. **Axiomatic Sieve Engine** : - Formal specification gatekeeper evaluating requirements against 5 negative invariants (`shall never` ), explicit mathematical bounds, deterministic state machines, and a 4-class error taxonomy. 5. Formal specification gatekeeper evaluating requirements against 5 negative invariants ( Inject perimeter rules, MCP server declarations, and pre-commit sentinels into your workspace: ``` ctxfw init --global ``` Automatically configures Google Antigravity, Cursor, and Claude Desktop. ``` ctxfw init --repo . ``` Deploys `.git/hooks/pre-commit` to prevent uncertified code commits lacking an attested specification brief. For distributed engineering teams requiring centralized policy controls: - **Team-wide LLM budget circuit breakers** : Hard token and dollar thresholds with automatic killswitches. - **Multi-node reverse proxy governance** : Centralized firewall gateways supporting OpenAI and Anthropic streaming SSE endpoints. - **FinOps Telemetry Ledger** : Aggregate tokens saved, cost elusion analytics, and tamper-evident audit trails. **Control Plane & Enterprise Licensing:** [https://ctxfw.heuristicolab.com](https://ctxfw.heuristicolab.com) ENGINEERED BY HEURISTICO LAB // SKUNK WORKS DIVISION HIGH-ASSURANCE DEFENSE SYSTEMS GROUP