Content-addressed, arbitrary-depth, circular-reflexive trees.
[dependencies]
fragmentation = { git = "https://github.com/systemic-engineering/fragmentation" }A Rust library for building trees where every node is identified by its
content. Two node types: Shard (terminal) and Fractal (recursive).
Git-compatible SHA-1 hashing at the wire boundary; content-addressed
SpectralCoordinate<5> internally. The observer is part of the commit,
not the hash.
As of 2026-06-01, fragmentation is also the substrate beneath
fragmentation-mcp — a standalone Model Context Protocol server
that exposes content-addressed primitives + the HamiltonScheduler's
hot/cold management to any agent runtime (Claude Code, Cursor, Zed,
any MCP-aware client). See docs/specs/fragmentation-mcp.md
for the architecture; the MCP layer lives in the new
vcs/mcp/ workspace member. Fragmentation-mcp is the first deployment
target of the wider stack — ships standalone, useful without mirror,
open-source infrastructure that fills a real gap in the agent-runtime
ecosystem (existing git-MCPs are CLI wrappers; this one speaks
content-addressed primitives directly).
use fragmentation::fragment::{Fragment, blob_oid};// Shard -- terminal nodelet leaf = Fragment::shard("hello");// Fractal -- recursive nodelet tree = Fragment::fractal("root",vec![leaf]);// Content-addressed: same content = same hashlet oid = tree.content_oid();Different witness, different commit. Same content, same tree. The observer changes the record without changing the content.
Fragmentation is graph-native DAG today (v1). Content addressing handles directed acyclic multi-parent references natively: same content → same OID, regardless of how many parents reference it.
Fractal::Branchcarriesfractal: Vec<Fractal<E, H>>by value. The same child node, cloned into two parents, collapses to one stored node under the content-address.Fractal::Lenscarriestarget: Vec<H>for explicit OID-only references (proper graph edges, not containment). Multiple lenses can point at the same target without duplication.
Cycle handling is deferred to spectral-db (v1.5). spectral-db
exercises actually-cyclic graphs with the witnessed-computation
contract: each cycle traversal records a measurement, the measurement
IS the fixed-point witness, and kintsugi ensures the measurement
converges. Fragmentation itself treats cycle detection as an error
class; the v1/v1.5 boundary is named in
docs/specs/mirror-native-vcs.md §4.6 (Consequence 3).
Fragmentation ships as a workspace with VCS-adjacent adapter crates:
| Crate | Role |
|---|---|
fragmentation | the substrate; content-addressed primitives, hash trait, store types |
fragmentation-git (vcs/git/) | git wire interop; SHA-1 ↔ SpectralCoordinate<5> crosswalk; FUSE portal; frgmt-git CLI |
fragmentation-jj (vcs/jj/) | jj-native backend (planned; per docs/specs/mirror-native-vcs.md) |
fragmentation-mcp (vcs/mcp/, new) | MCP server; agent-runtime substrate; fragmentation serve --stdio |
The substrate compiles dependency-free of all adapters; each adapter
pulls fragmentation as its dependency. prism_core stays zero-dep.
Fragmentation-mcp is the first deployment target of the wider
stack — ships standalone, useful without mirror, open-source
infrastructure that fills a real gap in the agent-runtime ecosystem
(existing git-MCPs are CLI wrappers; fragmentation-mcp speaks
content-addressed primitives directly, with bounded RAM via the
HamiltonScheduler and structured drops via [[docs/specs/lens-transit]]).
See docs/specs/fragmentation-mcp.md.
| Feature | What it enables |
|---|---|
git | Read/write fragment trees as native git objects |
ssh | Ed25519 signing + ECIES encryption (X25519, ChaCha20-Poly1305) |
gpg | GPG signing + encryption via subprocess |
| Module | Purpose |
|---|---|
fragment | Fragment<E>, construction, content addressing |
ref_ | Ref -- content address (SHA + label) |
sha | Sha -- SHA-1 and SHA-256 |
store | Content-addressed in-memory storage |
walk | Depth-first traversal, fold, find, depth |
diff | Positional structural comparison |
encoding | Text as five-level fragment trees |
witnessed | Commit metadata -- author, committer, timestamp, message |
git | Fragment persistence to git repositories |
keys | Sign, encrypt, decrypt (SSH, GPG, plain) |
actor | Witness identity with encoding boundary and keys |
See docs/.
cargo test --all-features # 185 tests