Tape Systems — Context as Architecture

A unified fact model for long-running, multi-team work.
It also extends to observability, eval, and training.
Practiced in bub.build, view source

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Tape

Chronological sequence of facts

Entry

An immutable fact record

Anchor

Logical checkpoint for state reconstruction

View

Task-oriented assembled context window

Invariants

History is append-only, never overwritten

Derivatives never replace original facts

Context is constructed, not inherited wholesale

Order is trackable via monotonic IDs

Old facts cannot be modified in-place

Corrections are made by appending, not deleting

Full history preserved before the anchor

Rebuild from anchor, skip full scans

Anchors can carry structured state payloads

Attach minimum inherited state

Shift execution origin past the new anchor

State Contract Example

{ phase: "implement",
  summary: "Discovery complete.",
  next_steps: ["Run migration", "Integration tests"],
  source_ids: [128, 130, 131],
  owner: "agent" }

Why Complex

Anchors can form non-linear graphs, not a single timeline

Memory views assemble from multiple nodes, guided by policy

Graph structure requires explicit lineage and provenance

Task as View Assembler

Here, Task is a special View Assembler: one task maps to one topic, assembling Task Schema, Task Config, Task Harness, and Task Description into a runtime-executable view; each DAG Node maps to one turn boundary inside that topic.

01schema

Task Schema

Declares task structure: node boundaries, dependencies, artifact contracts, and task presentation.

It answers which structure this task runs through.

02config

Task Config

Holds stable task-level configuration such as defaults, business rules, target environments, and external system constraints.

It answers which rules this task runs with.

03task

Task Description

Captures one task's business brief, scope, interpretation, delivery preference, and human confirmation.

It answers what this run should do.

04harness

Task Harness

Constrains executable agent behavior, for example with scripts/*.feature files that fix acceptance boundaries, run paths, and forbidden moves.

It answers what the agent must do and must not do.

05runtime

Runtime Source of Truth

After topic creation, runtime owns the authoritative projection; DAG anchors only record summaries, audit events, and lookup checkpoints.

Read runtime snapshots for state; read DAG anchors for boundary events.