Blobs ≤ BLOB_THRESHOLD_BYTES (900 KB) take the Contents API path (same as writeFile). Larger blobs use the Git Data API: POST blob, GET ref + commit, POST tree (with base_tree), POST commit, PATCH ref. Tests cover both paths plus error propagation. getBlob/deleteBlob are thin wrappers over readFile/deleteFile. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>