Tack

Tack is a horizontally scalable, multi-tenant project management platform: a replacement for Plane CE, Linear, and Jira, built for production scale from the first commit. It is not a personal tool or a prototype.

These are the durable principles that govern every decision. The binding architecture and rules live in AGENTS.md; the design docs and runbooks live in docs/. If this README and AGENTS.md ever disagree on a rule, AGENTS.md wins.

Every entity (org, workspace, project, state, label, issue, epic, cycle, module, comment, activity, custom type) is the same primitive: a node in FoundationDB with universal fields and a property map, connected by relationship edges. There are no special-case entity tables. A new kind of entity is data, not a code change. Behavior follows node-type metadata, never hardcoded type names.

The system is designed for N=many while it runs on one host. There is no single point of write contention and no coordinator a second node would have to fight. Growing from one node to many is configuration and operations, not a rewrite. We never ship a design that "works for now" and is meant to be fixed for scale later. If it will not scale, it does not ship.

We pay for scale-grade architecture before the load arrives, because retrofitting scale into a live multi-tenant system is the expensive and dangerous path. Early over-engineering here is a deliberate trade, not gold-plating. The default answer to "is this too much for current scale" is yes, and that is intended.

Not only the hot paths. Every read, every write, and every background job is designed as if it will be hammered, including the slices nobody predicted. There is no path that gets a pass because "this one is low traffic." Unexpected load on an unexpected slice is a first-class case, not an incident.

The type system is user-extensible. Hierarchy is a DAG defined by metadata, not a fixed tree. References, addresses, and behavior are declared as data. Strange, demanding, never-anticipated requirements are meant to be supported by the core design, not bolted on at the edges. The architecture is built to absorb the crazy case without a rewrite.

The org is the tenancy root. Tenant isolation is built into identity, storage locality, and authorization. It is never layered on after the fact, and no feature is designed as if there were a single tenant.

• AGENTS.md: the binding contract, the configs/tack deploy seam, the settled decisions, and the architecture.
• docs/plans/: forward design, including the audit subsystem horizontal design and the Kafka cutover.
• docs/runbooks/: recovery and operational procedures.
• The code is the source of truth for concrete values: FDB keys in internal/adapters/foundationdb/keys.go, SQL schema in migrations/, config in internal/config/config.go, and the stack in docker-compose.yml.