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Tower

The tower is a centralized agent responsible for merge coordination. There is exactly one tower per repository.

Aviation Analogy​

At an airport, the control tower manages all takeoffs and landings — sequencing aircraft, granting clearance, and ensuring planes don't collide on the runway. ATC's tower does the same for code merges — it controls the merge queue, verifies readiness, and sequences merges to avoid conflicts.

Responsibilities​

The tower has three core jobs:

1. Maintaining the Merge Queue​

When a craft passes its landing checklist and requests clearance, the tower adds it to the merge queue. By default, merges are sequenced first-come, first-served.

2. Granting or Denying Clearance​

Before granting landing clearance, the tower verifies:

  • All vectors in the craft's flight plan have been reported as passed
  • The craft's branch is up to date with main

If either check fails, the craft is denied clearance.

3. Executing the Merge​

Once cleared, the tower merges the craft's branch into main and marks the craft as Landed.

Rules​

  • RULE-TOWER-1: There must be exactly one tower per repository.
  • RULE-TOWER-2: The tower must verify all vectors in a craft's flight plan have been reported as passed before granting landing clearance.
  • RULE-TOWER-3: The tower must verify the craft's branch is up to date with main before executing a merge.

Example​

Tower merge queue:

  Position 1: feat-auth-flow
    Vectors: 4/4 passed ✅
    Branch up to date: ✅
    Status: Merging...

  Position 2: fix-rate-limiter
    Vectors: 3/3 passed ✅
    Branch up to date: ❌ (needs rebase)
    Status: Sent on go-around to rebase

  Position 3: refactor-logging
    Vectors: 5/5 passed ✅
    Branch up to date: ✅
    Status: Waiting for position 1 to clear