Action State Group Many systems emit individually signed records — receipts, attestations, statements — and store them locally. Each record verifies on its own, but the collection proves nothing: records can be deleted, reordered, or created after the fact without detection. This document specifies the Checkpointed Local Log (CLL): a producer- operated append-only log, built on the Merkle Mountain Range structure whose COSE proof formats are specified in [I-D.bryce-cose-receipts-mmr-profile], together with a small signed checkpoint that commits to the log's entire history. Records of any format are appended as they are produced; checkpoints are emitted on a declared cadence and may be registered with one or more independent Transparency Services or witnesses using existing SCITT registration. A CLL upgrades a set of point receipts into a stream with provable order, contemporaneity, and completeness — while defining precisely, and narrowly, what such a log does and does not establish. This document defines the log discipline and the checkpoint structure; it defines no new proof formats, no transparency service behavior, and no payload semantics.