hephaestus/docs/reference/heph-nvim.md

---
title: heph.nvim
modified: 2026-06-01
tags:
  - reference
  - design
---

# heph.nvim

The primary user surface (tech-spec §8): a Neovim plugin that replaces
obsidian.nvim and is a **thin client of the local `hephd`** over its
unix-socket JSON-RPC. Notes, journals, and tasks are edited as ordinary
buffers; the daemon owns all storage and sync. Built in checkpointed slices on
`feature/v1-prototype`; this card tracks the stable surface as it lands.

## Architecture

`heph.nvim/lua/heph/` modules, each small and single-purpose:

| Module | Responsibility |
|---|---|
| `rpc` | libuv (`vim.uv`) unix-socket JSON-RPC client. A blocking `call()` is built over the async pipe by pumping the loop with `vim.wait` until the matching id returns. Demuxes responses by id; partial lines are buffered; JSON `null` decodes to Lua `nil` (`luanil`). A `Session` is one connection — the module keeps a default singleton and lets tests open isolated sessions. |
| `node` | Buffer-backed nodes. A node is a buffer named `heph://node/<id>` with `buftype=acwrite`; `BufReadCmd` loads the body via `node.get`, `BufWriteCmd` saves the whole buffer via `node.update`. |
| `link` | Parse the `[[wiki-link]]` under the cursor (mirroring `extract.rs` grammar) and follow it via `node.resolve` (exact, never fuzzy `search`). Unresolved links are allowed. |
| `journal` | Open/create a dated journal node (idempotent — deterministic id). |
| `daemon` | Locate / spawn / readiness-poll `hephd` (shared with the e2e harness). |
| `config` / `init` | `setup(opts)`, socket resolution, default keymaps. |
| `command` | The `:Heph <subcommand>` dispatch + completion. |

Surfaces never touch SQLite — every operation is a daemon RPC (tech-spec §3).
The plugin is **mode-agnostic**: Tactical/Strategic/Organizational are
plugin-side compositions of daemon primitives, not daemon concepts.

## Daemon RPC dependencies

Beyond the existing methods (tech-spec §6), the plugin relies on
**`node.resolve {title} → Node | null`**: an exact, owner-scoped,
non-tombstoned alias-then-title match — the same mapping the store uses to
materialize `wiki` links, so "follow link under cursor" jumps to the *same*
node the stored link points at.

## Commands (as of slice 11a)

| Command | Action |
|---|---|
| `:Heph today` | Open today's journal |
| `:Heph journal <YYYY-MM-DD>` | Open a dated journal |
| `:Heph follow` (also `<CR>` in a node buffer) | Follow the `[[link]]` under the cursor |
| `:Heph open <id>` | Open a node buffer by id |

Task/agenda views (`:Heph next`/`list`/`capture`, set-attention, done/drop),
the per-task log, and context-item **promotion** arrive in slices 11b/11c.

## Testing (tech-spec §9)

The headless e2e suite drives the plugin in `nvim --headless` against a real
`hephd` over a temp socket, asserting both buffer contents and resulting DB
state (via an isolated RPC session). It uses a **self-contained busted-style
runner** (`tests/e2e/runner.lua`) — no external plugins, no network — so it is
deterministic. `mise run test-nvim` builds the daemon and runs the suite against
system-installed Neovim; a deliberately failing spec exits non-zero (no
false-green). In CI the same suite runs inside a Dagger container that provides
Neovim + the Rust toolchain (slice 11c).

## Related

- [[tech-spec]] — §8 surface spec, §6 RPC API, §9 testing strategy
- [[design]] — the mode model (Tactical/Strategic/Organizational) and rationale