tidaldb/CLAUDE.md

Jon Gjengset: I don't ship what I wouldn't trust at 3am during a production incident. Pay attention to what the user says and follow it. Do not make them repeat themselves.

tidalDB

A single-node-first, embeddable Rust database for the personalized content ranking problem. Replaces the 6-system stack (Elasticsearch + Redis + Kafka + feature store + vector DB + ranking service) with a single process, single query interface, and single operational model.

Status: Vision and specification phase. No implementation yet.

Find Your Guide

If you need to...	Read this
Understand the vision	VISION.md
See use cases and surfaces	USE_CASES.md
See sequence diagrams	SEQUENCE.md
Understand the system architecture	ARCHITECTURE.md
Look up domain concepts	ai-lookup/index.md
Follow coding standards	CODING_GUIDELINES.md
See the API spec	API.md
Read architectural lessons	thoughts.md
Read technical research	docs/research/

Agents

Agent	Identity	Use when
@tidal-engineer	Jon Gjengset	Implementing features, designing storage internals, building the signal system, debugging correctness issues
@tidal-visionary	Spencer Kimball	Planning roadmaps, defining milestones, scoping phases, making build-vs-defer decisions
@tidal-researcher	Andy Pavlo	Investigating best practices, surveying prior art, evaluating libraries, producing research documents
@tidal-storyteller	—	Building the marketing site, writing blog posts, crafting public-facing copy

Skills

Phase Lifecycle

Step	Skill	Use when
1. Plan	/milestone	Planning task documents for a milestone phase (orchestrates all 3 agents)
2. Build	/implement	Executing a planned phase task-by-task (delegates to @tidal-engineer)
3. Review	/review	Reviewing completed phase against spec and coding standards (delegates to @tidal-engineer)
4. Accept	/uat	User acceptance testing a reviewed phase (delegates to @tidal-engineer)

Other Skills

Skill	Use when
/tidal-deliver-task	End-to-end feature delivery orchestrating all 4 agents (scope -> research -> build -> review -> accept)
/tidal-verify-completion-to-spec	Joint spec verification from all 3 agent lenses in parallel (product fit, research grounding, implementation correctness) — use any time, not just after /implement
/develop	Quick implementation work outside the milestone lifecycle
/research [topic]	Investigating best practices, evaluating approaches (delegates to @tidal-researcher)
/roadmap	Building or updating the milestone roadmap (delegates to @tidal-visionary)
/build-site	Creating or iterating on the marketing site
/write-blog	Writing blog posts about progress or architecture

Core Domain Model

• Entities: Items (content), Users, Creators — each with metadata, embedding slot, signal ledger
• Signals: Typed, timestamped event streams with native decay, velocity, and windowed aggregation
• Relationships: Weighted, directional edges between entities (follows, blocks, interactions)
• Ranking Profiles: Named, versioned scoring functions declared in schema
• Query: Single operation combining retrieval, filtering, ranking, and diversity enforcement

Ports

Dev servers use port range 59520–59529 (e.g. site/ on 59520).

Critical Rules

• Scope: This is NOT a general-purpose database. Every decision serves one question: "given a user and a context, what content should they see, in what order?"
• Embeddings: The database retrieves and ranks over vectors. It does NOT generate them.
• Signals are primitives: Decay, velocity, and windowed aggregation are native — not application logic.
• Single-node first: Embeddable. Scales vertically before horizontally.
• Language: Rust.

Repository Structure

.                    # Top-level docs and configuration
├── CLAUDE.md        # This file — project instructions
├── VISION.md        # Product vision and thesis
├── USE_CASES.md     # 14 use cases, all discovery surfaces
├── SEQUENCE.md      # Data flow sequence diagrams
├── CODING_GUIDELINES.md  # Engineering standards
├── API.md           # API specification
├── thoughts.md      # Architectural lessons from sister projects
├── ai-lookup/       # Domain concept reference
├── docs/            # Research and documentation
│   └── research/    # Deep technical research docs
├── .claude/         # Claude Code configuration
│   ├── agents/      # Agent definitions
│   └── skills/      # Skill definitions
├── tidal/           # Rust database engine
│   ├── Cargo.toml
│   ├── src/
│   │   ├── storage/ # Entity store, signal ledger, inverted index, HNSW
│   │   ├── query/   # Query parser, planner, executor
│   │   ├── ranking/ # Profile engine, signal scoring, diversity enforcement
│   │   ├── signals/ # Signal types, decay, velocity, windowed aggregation
│   │   └── schema/  # Schema definition, validation, migrations
│   ├── benches/     # Performance benchmarks
│   └── tests/       # Integration and property tests
└── site/            # Public marketing site (Next.js)

Pre-commit Hooks

The pre-commit hook runs automatically on staged files:

• tidal/ (Rust): cargo fmt (auto-fix + re-stage), cargo clippy -D warnings, cargo test --lib
• site/ (Next.js): eslint (if node_modules installed)

All cargo commands use --manifest-path tidal/Cargo.toml since the Rust project is not at repo root.

Tests must be fast. Slow or hanging tests are bugs — diagnose root cause, then remove, fix, or refactor; never leave them hanging.