# Completed Plans

Archive of implementation plans that have been executed and shipped.

## Content Addressing — COMPLETED ✓

**Completed:** March 2026

hash-based fetch, in-memory index, mirror foundation. All five implementation steps completed:

1. ✅ `content-hash` added to FETCH responses — SHA-256 of stripped body in metadata
2. ✅ Hash index in Store — `BuildHashIndex()`, `LookupHash()`, `UpdateHashIndex()`, `RemoveHashEntry()`
3. ✅ Index updates on writes — `Write()`, `SetArchived()` keep index synchronized
4. ✅ Hash-based FETCH — `isHashPath()` validates `/sha256-<64hex>`, `handleFetchByHash()` retrieves by hash
5. ✅ Startup initialization — `BuildHashIndex()` called on server startup

**Key implementation details:**
- Response metadata includes `content-hash: sha256-<64hex>` (stripped body, not including store frontmatter)
- Hash paths `/sha256-<hex>` detected by pattern match in FETCH handler
- Read auth checked after hash resolves to real path (auth bypasses prevented)
- Hash-based paths protected from writes (PUBLISH, APPEND, ARCHIVE reject them)
- Current versions only indexed (archived docs excluded)
- In-memory index rebuilt on startup from content directory

**Files:**
- `server/internal/handler/handler.go` — `content-hash` in responses, hash path detection, `handleFetchByHash`
- `server/internal/store/store.go` — hash index struct, `Build/Lookup/Update/Remove` methods
- `server/cmd/demarkus-server/main.go` — `BuildHashIndex()` call on startup
- Tests in `handler_test.go` and `store_test.go`

**Foundation for:** Federation (mark_index/mark_resolve), content-addressed mirroring, distributed caching

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## Federation — COMPLETED ✓

**Completed:** March 2026 (Phase 3)

Agent-driven hash discovery, mark_index, mark_resolve. Built on content addressing.

**Shipped:**
- `mark_index` MCP tool — crawls source server, collects hashes, publishes index to hub
- `mark_resolve` MCP tool — resolves content by hash using hub index
- `client/internal/index` package — Parse, Build, Merge for markdown hash index documents
- Manifest check on index publish, `force` override, `dry_run` mode, 1000 doc cap
- Enables hub-based discovery and content resolution

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## Persistent Graph — COMPLETED ✓

**Completed:** March 2026 (Phase 4)

Disk-backed graph store, incremental crawl, backlinks. Information is findable through connections.

**Shipped:**
- `client/internal/graphstore` package — nodes, edges, etags, timestamps, atomic writes, schema versioning
- `CrawlAndPersist` — unified crawl + merge + save, nil-safe, shared across all clients
- `mark_backlinks` MCP tool — reverse link lookup, "what links here?"
- Graph export — `Store.Export()` renders as publishable markdown, `ParseExport()` parses back
- TUI graph view — Links (BFS), Backlinks (reverse edges), Topology (all nodes sorted by importance)
- Graph seeding — TUI graph loads instantly from stored graph while crawl runs in background
- Cell escaping — handles pipes and backslashes in titles, rune-safe UTF-8 truncation

**Foundation for:** Agent discovery, network topology mapping, content resilience