Lifecycle visualizer

Four statuses. Six transitions. Nothing else.

Object lifecycle

select a transition

CREATEMARKROTATECLOSEREFUNDAny other spend

Six transitions, and nothing else

A Tandem object has exactly four statuses and exactly six ways to move between them. There is no operation that removes a chapter, renumbers a sequence, merges two objects, splits one, or hands an object to a third party. Select a transition to see what it requires and what it changes.

Transitions from section 10 of the normative specification. Effects matchapplyStateTransition in src/protocol/state-engine.ts.

The two numbers that tell you what happened

You can reconstruct an object’s ending from its final state alone, without reading a single transaction.

If the object is	And the sequence	Then it ended by
CLOSED	one higher than the last chapter or rotation	both parties agreeing
REFUNDED	unchanged from its last operation	either party broadcasting a refund both had signed, once the carrier was 52,560 blocks old
EXITED_NONCANONICAL	unchanged from its last operation	a spend that was not a valid operation
ACTIVE	still advancing	it has not

That is why the sequence rules are worth memorising. A close is a state transition and advances the sequence. Recovery and a non-canonical exit are terminations that record the sequence they found.

Operations that do not exist

Being explicit about the absent operations is as useful as describing the present ones. There is no way to:

• remove or renumber a chapter
• merge two objects, split one, or fork one
• transfer an object to a third party who was never one of the two keys
• revive a terminal object, except by a reorganization that removes its terminal spend
• add a third participant
• change the carrier value, the founding window, or the recovery delay for one object

None of these are unimplemented features. The specification states that Tandem never combines, splits, or forks objects, and that no rule grants an administrator, coordinator, content host, indexer, wallet, or issuer authority to change keys, sequence, commitments, founding status, object status, roots, or supply.

Drive it yourself

0active

chapters

0

founding

yes

carrier

20,000 sats

key0

036b86a…48d410

key1

03c5a60…eba93d

address

bcrt1qztq6…shh5x7f

The record so far1 entry

CREATEseq 0

Both parties signed. The object exists at sequence 0 with no chapters yet.

Write a chapterAdds one entry. Keys stay the same.Rotate controlSwaps both keys. History is untouched.Close togetherBoth sign. Equal payouts.Broadcast the refundPre-signed by both. Needs 52,560 blocks.Spend it another wayThe object terminates.Start over

This is a teaching model. It runs entirely in this page, builds no transaction, and touches no Bitcoin network. The rules it follows are the ones insrc/protocol/state-engine.ts.

For the same transitions stated in the specification’s own terms, including the exact counter definitions, read object lifecycle.