tidemark

Snapshot a directory tree and diff exactly what changed - no git required.

A tidemark is the line a receding tide leaves behind, recording the level the water reached so you can see how things stood before. tidemark does the same for a directory: leave a mark, do anything, then see precisely what was added, modified, deleted, or renamed.

It scores 100/100 against The CLI Spec: structured output, schema introspection, clean stdout/stderr separation, non-interactive by default, idempotent operations, and bounded output. Excellent for humans at a terminal and for AI agents in a pipeline.

Why

"What did that command actually do to my files?" is a question without a good answer today. git needs a repo and pollutes the tree; fsdiff was archived; copy-based tools need two full copies. tidemark is a small, deterministic (BLAKE3) witness that answers it in one bounded call.

Install

cargo install tidemark
brew install rvben/tap/tidemark

Quick start

Human workflow with a labeled checkpoint:

tidemark snap before        # checkpoint the current tree
make install                # do the risky thing
tidemark diff before        # colored table of what changed

Agent / CI workflow with a portable manifest:

tidemark snap -o pre.tidemark        # write a manifest file (use - for stdout)
./run-some-tool
tidemark diff pre.tidemark @ --json  # bounded JSON delta in one call

Commands

Useful flags

• snap: --path DIR, --ignore GLOB (repeatable), --hidden, --no-ignore, --no-content (smaller manifest, disables content diffs), --force (overwrite a label whose tree differs).
• diff: --content (real unified line diffs for text files), --only added,modified,deleted,renamed, --exit-code.
• Global (accepted on any command): --output json|table (defaults to JSON when piped, a table on a TTY), --json (shorthand for --output json), --quiet (suppress the stderr summary), --yes (confirm destructive ops), and the bounded-output flags --limit N, --offset N, --fields a,b for list and diff.

What counts as a change

Each entry records its BLAKE3 content hash, size, Unix mode, and symlink target. A file is modified when its content, mode, or symlink target changes. A rename is detected when a deletion and an addition share the same content hash and mode (and the pairing is unambiguous - duplicate-content files stay as plain add/delete). mtime is recorded for information but never triggers a change, so touch and rebuilds do not create false positives.

Small UTF-8 files (up to 256 KiB) also store their text inline so diff --content can show real before/after line diffs, even between two stored manifests. Pass --no-content to skip this.

Output

Snapshots of an unchanged tree produce an identical tree_digest - that is the idempotency signal. diff JSON is a flat object with summary counts and a bounded changes array; list uses the standard envelope:

{ "items": [ ... ], "total": 3, "limit": null, "offset": 0 }

Exit codes

• Default: 0 success, 2 error.
• With --exit-code (the diff(1) convention): 0 no changes, 1 changes found, 2 error.

Errors are written to stderr as {"error": {"kind": "...", "message": "...", "retryable": <bool>}}. Kinds: not_found, conflict, invalid_input, io (retryable), unsupported.

See AGENTS.md for the agent-focused contract.

Development

All CI steps are make targets, so the pipeline only runs make:

make check   # fmt-check + clippy (-D warnings) + tests + doctests
make score   # build release and score against clispec
make ci      # check + score

License

MIT