ThumbGate

Pre-action gates that physically block AI coding agents from repeating known mistakes. Capture feedback, auto-promote repeated failures into prevention rules, and enforce them via PreToolUse hooks. This is a reliability layer for one sharp agent, without another planner or swarm.

Honest disclaimer: this is not RLHF weight training. It is context engineering plus enforcement. Feedback becomes searchable memory, prevention rules, and gates that block known-bad actions before they execute.

Works with Claude Code, Codex, Gemini, Amp, Cursor, OpenCode, and any MCP-compatible agent. Verification evidence lives in docs/VERIFICATION_EVIDENCE.md.

Why it exists

Most memory tools only help an agent remember. ThumbGate also enforces.

recall injects the right context at session start.
search_lessons shows promoted lessons plus the corrective action, lifecycle state, linked rules, linked gates, and the next harness fix the system should make.
search_rlhf searches raw RLHF state across feedback logs, ContextFS memory, and prevention rules.
Pre-action gates physically block tool calls that match known failure patterns.
Session handoff and primer keep continuity across sessions without adding an extra orchestrator.

Free and self-hosted users can invoke search_lessons directly through MCP, and via the CLI with npx mcp-memory-gateway lessons.

Tech Stack

Core runtime

Node.js >=18.18.0
Module system: CommonJS CLI/server runtime
Primary entry points: CLI, MCP stdio server, authenticated HTTP API, OpenAPI adapters

Interfaces

MCP stdio: adapters/mcp/server-stdio.js
HTTP API: src/api/server.js
OpenAPI surfaces: openapi/openapi.yaml, adapters/chatgpt/openapi.yaml
CLI: npx mcp-memory-gateway ...

Storage and retrieval

Local memory: JSONL logs in .claude/memory/feedback or .rlhf/*
Lesson DB (v0.8.0): SQLite + FTS5 full-text search via better-sqlite3 — dual-written alongside JSONL. Indexed by signal, domain, tags, importance. Replaces linear Jaccard token-overlap with sub-millisecond ranked search.
Corrective actions (v0.8.0): On negative feedback, capture_feedback returns correctiveActions[] — top 3 remediation steps inferred from similar past failures by tag/domain overlap.
Context assembly: ContextFS packs and provenance logs
Default retrieval path: SQLite FTS5 (primary) with JSONL Jaccard fallback
Semantic/vector lane: LanceDB + Apache Arrow + local embeddings via Hugging Face Transformers

Enforcement and automation

PreToolUse enforcement: scripts/gates-engine.js
Hook wiring: init --agent claude-code|codex|gemini
Browser automation / ops: playwright-core
Social analytics store: better-sqlite3

Billing and hosting

Billing: Stripe
Hosted API / landing page: Railway
Worker lane: Cloudflare Workers in workers/

Quick Start

# Install MCP server for your agent
claude mcp add rlhf -- npx -y mcp-memory-gateway serve
codex mcp add rlhf -- npx -y mcp-memory-gateway serve
amp mcp add rlhf -- npx -y mcp-memory-gateway serve
gemini mcp add rlhf "npx -y mcp-memory-gateway serve"

# Or auto-detect supported agents
npx mcp-memory-gateway init

# Auto-wire PreToolUse hooks
npx mcp-memory-gateway init --agent claude-code
npx mcp-memory-gateway init --agent codex
npx mcp-memory-gateway init --agent gemini

# Health and core workflows
npx mcp-memory-gateway doctor
npx mcp-memory-gateway lessons
npx mcp-memory-gateway dashboard

What Actually Works

Actually works	Does not work
`recall` injects past context into the next session	Thumbs up/down changing model weights
`session_handoff` and `session_primer` preserve continuity	Agents magically remembering what happened last session
`search_lessons` exposes corrective actions, lifecycle state, linked rules, linked gates, and next harness fixes	Feedback stats automatically improving behavior by themselves
Pre-action gates block known-bad tool calls before execution	Agents self-correcting without context injection or gates
Auto-promotion turns repeated failures into warn/block rules	Calling this “RLHF” in the strict training sense
Rejection ledger shows why vague feedback was rejected	Vague signals silently helping the system

How it works

Capture structured feedback with context, tags, and optional reasoning traces.
Validate signals and reject vague or unsafe entries before promotion.
Promote useful feedback into searchable memory and principle/rule material.
Auto-generate prevention rules from repeated failures.
Enforce those rules through PreToolUse hooks before risky tool calls run.
Expose the full state through MCP tools, the API, dashboards, and verification reports.

The serve command also runs a background watcher for external JSONL writes from hooks, CI, or companion tools.

Core Tools

Essential profile

These tools are the shortest path to value:

Tool	Purpose
`capture_feedback`	Accept up/down signal + context, validate, promote to memory
`recall`	Recall relevant past failures and rules for the current task
`search_lessons`	Search promoted lessons with corrective action, lifecycle state, rules, gates, and next harness fixes
`search_rlhf`	Search raw RLHF state across feedback logs, ContextFS, and rules
`prevention_rules`	Generate prevention rules from repeated mistakes
`enforcement_matrix`	Inspect promotion rate, active gates, and rejection ledger
`feedback_stats`	Approval rate and failure-domain summary
`feedback_summary`	Human-readable recent feedback summary
`estimate_uncertainty`	Bayesian uncertainty estimate for risky tags

Use the lean install when you want recall, gates, and lesson search first:

RLHF_MCP_PROFILE=essential claude mcp add rlhf -- npx -y mcp-memory-gateway serve

Free and self-hosted users can invoke search_lessons directly through MCP to inspect corrective action per lesson. For broader retrieval across feedback logs, ContextFS memory, and prevention rules, use search_rlhf through MCP or the authenticated GET /v1/search API.

Dispatch profile

For phone-safe remote ops, use the read-only dispatch surface:

RLHF_MCP_PROFILE=dispatch claude mcp add rlhf -- npx -y mcp-memory-gateway serve
npx mcp-memory-gateway dispatch

Guide: docs/guides/dispatch-ops.md

Pre-Action Gates

Gates are the enforcement layer. They do not ask the agent to cooperate.

Agent tries git push
→ PreToolUse hook fires
→ gates-engine checks rules
→ BLOCKED (for example: no PR thread check)

Built-in examples include:

push-without-thread-check
package-lock-reset
force-push
protected-branch-push
env-file-edit

Define custom gates in config/gates/custom.json.

Architecture

Pipeline: Capture → Validate → Remember → Distill → Prevent → Gate → Export

Context Engineering Architecture

For deeper packaging and topology details:

Operator Contract

If you are running autonomous agents against this repo or another repo that uses this workflow, keep these entry points visible:

WORKFLOW.md: scope, proof-of-work, hard stops, and done criteria for agent runs
.github/ISSUE_TEMPLATE/ready-for-agent.yml: bounded intake template for ready-for-agent work
.github/pull_request_template.md: proof-first PR handoff format

Commercial and Proof Surfaces

License

MIT. See LICENSE.

mcp-memory-gateway