GraphError

The run was cancelled by interrupting its thread - RunHandle.cancel in a runtime, or interrupting the thread driving CompiledGraph.step. Every task was interrupted and joined. In a runtime, tasks that finished first keep their results as pending writes, and the checkpoint stays Running, so recover continues it without re-running them. A step keeps nothing from the cancelled superstep, and returns this with the interrupt flag set.

A new checkpoint's parent is not the thread's latest: another writer advanced the thread.

The thread has no checkpoint checkpointId in its history: it never had one, or retention (Checkpointer.prune), a guardrail Block (which retracts its turn) or deleteThread removed it. Nothing was changed.

The checkpointer refused or failed a commit; the run stops at its last durable checkpoint. runError is the run's own failure when the commit failed while recording it.

The run's RunBudgets.timeout, measured from its claim, expired: the run was stopped exactly as by Cancelled, and a RunEvent.RunTimedOut event was committed against lastCheckpoint. The checkpoint stays Running, so recover with a new budget continues the run without re-running tasks that had finished.

An execution was passed to a graph other than the one that created or restored it.

start was called on a thread whose latest checkpoint is mid-execution; use recover.

A commit is malformed, such as a pending write naming a checkpoint other than the latest.

The builder found one or more structural problems; every problem is listed.

A resume was refused: no answers, an interrupt that is not parked, or an answer that does not decode.

A node returned a route this graph cannot schedule.

A middleware hook threw: the run fails, the checkpoint stays Running, and recover re-runs only that task. middleware is the middleware's id.

A node returned a failure or threw.

resume was called on a thread that is not suspended.

recover was called on a thread with no incomplete execution.

start or recover was called on a suspended thread; answer its interrupts with resume.

Events before earliestSeq were compacted away and cannot be replayed.

A snapshot does not match this compiled graph; every problem is listed.

An unexpected throwable - such as a Clock that threw - refused the run at admission, or ended it where it was; a checkpointer whose commit throws is reported as CheckpointWriteFailed instead. Its thread claim is released; whatever the store holds for the thread stands.

A commit, renewal or release presented a fencing token that is not the thread's current claim: the claim was taken over after it expired, was released, or never existed. A Checkpointer refuses such a commit atomically, applying nothing and numbering no event, so a writer that lost its claim cannot record anything after another run took the thread over. current is the token of the thread's current claim, if there is one.

A key's update function rejected an update.

The run reached its superstep limit with work still scheduled.

The run's tenant is not the thread's: a thread belongs to the tenant recorded on its latest checkpoint, and requested (the caller's RunConfig.tenantId) is not it. None and Some differ. Nothing was changed. The owning tenant is deliberately not carried or printed, so a caller from another tenant learns nothing about the thread.

Another run holds the thread: it is still executing in this runtime, another runtime or process holds a live claim on it (RunClaim), or it claimed the thread between this call reading it and claiming it. Nothing was accepted or discarded - retry once that run has suspended or completed, or once its claim has expired. holder is the run id of the claim's holder when it is known and the caller may see it: it is never named for a thread that has no checkpoint yet in the store, whose tenant cannot be checked.

A fork's target thread already exists; a fork only ever creates a new thread. Nothing was changed.

A tool call failed the run: the tool returned Fatal, or broke its contract (an update to a key it does not declare, a question it does not declare). cause says which.

A node emitted an update for a key outside its declared write set.

A key was read or written that the graph did not register, or another key shares its id.

The graph went quiescent while a join still waited for arrivals that nothing can produce.

A checkpoint was written in a format this build does not read.

The names of the product elements

The name of the type