GitNexus for Agent Zero

Gives Agent Zero code-graph superpowers by installing the GitNexus CLI and registering its MCP server, so the agent can analyze a codebase — dependencies, impact/blast-radius, symbol callers, route/tool maps, and ad-hoc graph (Cypher) queries — before it changes anything.

Support

If this plugin is useful to you, you can support the developer.

What it can do

• Code-graph queries (gitnexus-code-graph skill) — once enabled, GitNexus's MCP tools appear in the agent's toolset: list indexed repos, find a symbol's callers, gauge the blast radius of an edit, map routes/tools, and run Cypher queries over the graph.
• Visual code graph in the Canvas (gitnexus-canvas-view skill) — adds a GitNexus icon to Agent Zero's right-side Canvas rail. Click it to explore an indexed repository's graph (symbols, dependencies, execution flows) and file tree right inside Agent Zero. Because GitNexus's web UI is local-only (it talks to its server over localhost), the plugin renders it in a headless Chromium inside the container and streams that view to the Canvas — everything stays on 127.0.0.1, nothing is exposed externally. (Needs a Chromium in the environment; the plugin installs one via apt if none is present. The MCP tools work regardless.) The repo list auto-refreshes: when you index or re-index a repo, the surface reloads itself within a couple of seconds (and on open) so the new/updated repo appears — no manual refresh, and the code word-wrap is preserved. The reload only happens when the index actually changed, so it won't disturb your view otherwise. You can also select text in the surface and Ctrl/Cmd+C to copy it to your own machine's clipboard (the code view and detail panels are made selectable for this), and Ctrl/Cmd+V to paste your local clipboard into a field on the surface. It's cross-platform; copying uses the async Clipboard API on https/localhost with a legacy fallback for plain-http LAN access.
• Scheduled re-index — keeps your indexed graphs fresh. Opt-in (off by default) — turn it on and the plugin registers a recurring Agent Zero scheduled task ("GitNexus re-index", Sundays 06:00 by default) that re-runs gitnexus analyze on any repo you've already indexed whose latest commit has changed since it was last indexed. It does not discover or index new repos — that's your call. See Keeping indexes fresh.

Setup

1. Install via the Plugin Hub, a GitHub repo URL, or by uploading the plugin ZIP, then enable it in the Plugins list.
2. On first run the plugin installs the gitnexus CLI (npm install -g gitnexus) and registers gitnexus mcp as a stdio MCP server in Agent Zero's MCP settings. Restart / re-enable so the MCP server connects.
3. That's it — no API key. Ask something like "what depends on this function?" or "map this repo" and the agent will use the GitNexus tools.

Requires Node.js/npm in the Agent Zero environment (present in the standard Docker image) and outbound network access on first run to install the CLI.

Note on onnxruntime-node: gitnexus pulls in onnxruntime-node for its optional local-embeddings (--embeddings) feature, and that dependency's native installer downloads a NuGet runtime that fails to unpack in some environments — which would otherwise abort the whole CLI install. The plugin doesn't use embeddings, so it installs gitnexus with ONNXRUNTIME_NODE_INSTALL=skip: only that one optional download is skipped, while gitnexus's required native pieces (its graph-DB engine and language grammars) build normally. You get a fully working CLI (MCP, analysis, Canvas, all core languages), just without local embeddings.

How it works

The plugin registers a standard MCP server entry under Agent Zero's mcp_servers setting:

"gitnexus": { "type": "stdio", "command": "gitnexus", "args": ["mcp"] }

Agent Zero spawns gitnexus mcp and exposes its tools to the agent. Because A0 reloads MCP automatically when that setting changes, the server connects without manual configuration.

Keeping indexes fresh

A GitNexus index is a snapshot — it reflects a repo at the commit it was analyzed at, so it drifts out of date as you keep committing. To keep it current the plugin can register a scheduled task — opt-in, off by default. Turn Scheduled re-index on in the plugin's Config panel and the task is registered; turn it off and it's removed — the toggle takes effect immediately, no restart:

• Task name: GitNexus re-index (visible in Agent Zero's Scheduler; set its cadence in the plugin's Config panel).
• Default cadence: Weekly (Sundays at 06:00), in Agent Zero's configured timezone — change it in the Config panel (Interval preset or Custom cron).
• What it does each run: reads the GitNexus registry and, for every repo you've already indexed that is a git work-tree, compares the repo's current HEAD against the commit it was last indexed at. If they differ, it runs an incremental gitnexus analyze on that repo; if not, it skips it (so an idle week does almost no work).
• What it does not do: it never indexes new repos. You decide what to index (gitnexus analyze <path>); the task only keeps current what you already chose.

How it's wired

The work and the schedule are deliberately separated:

• A deterministic helper does all the work. helpers/reindex.py is plain Python — it reads the registry, does the commit comparison, and runs gitnexus analyze on the repos that changed. No model/LLM is involved in the indexing logic itself.
• The scheduled task is purely the visible trigger. The GitNexus re-index task carries no logic; its instruction is just "call the gitnexus_reindex tool once and report the summary." It exists so the schedule is something you can see, run on demand, disable, or delete from the Scheduler UI (the cadence itself is set in the Config panel).
• Triggering goes through the agent loop. Agent Zero runs every scheduled task by handing its prompt to the agent (that's the only execution path A0 has), so when the task fires the agent's single action is to call the built-in gitnexus_reindex tool, which runs the helper in-process (no terminal/code-execution session — so a manual Run from the Scheduler works the same as a scheduled run). There is no background thread — nothing runs the helper except this task, so it never double-fires.
• Cost: because the trigger passes through the agent, each run spends a small amount of the model's budget on that one "run this command" hop — not on the indexing, which is the deterministic helper's job.

Setting the schedule

The cadence lives in the plugin's Config panel — the config is the source of truth (applied on save and on every boot, so editing the task's schedule directly in the Scheduler gets overwritten; change it here instead):

• Interval — a preset dropdown: every 6h / 12h, Daily, Weekly (the default), or Monthly. Daily/weekly/monthly run at 06:00.
• Custom schedule (cron) — a 5-field crontab (minute hour day month weekday) for anything the presets can't express (e.g. 0 3 * * * = daily at 03:00). Overrides the interval when set.
• Reset context each run — clear the task's conversation after each run so its context can't grow unbounded (on by default).
• Timezone — set reindex.timezone in the config to differ from Agent Zero's default.

The task still appears in Agent Zero's Scheduler, where you can see its history, Run it on demand, or disable/delete it. To turn the whole feature off, switch Scheduled re-index off in the Config panel (it removes the task).

Limitations: repos indexed with --skip-git (or non-git folders) have no commit to compare, so they aren't auto-refreshed; re-index those manually.

Configuration

default_config.yaml (override per scope in the plugin config UI):

Uninstalling

Uninstall through the Plugins UI. The uninstall hook removes the GitNexus re-index scheduled task, removes the gitnexus entry from your mcp_servers setting (Agent Zero reloads MCP) and, if this plugin installed the gitnexus CLI, uninstalls it too — so nothing is left behind. Your indexed repos and their .gitnexus data are left untouched. A gitnexus you had installed independently beforehand is left untouched. (A manual rm -rf of the plugin folder bypasses this hook — always uninstall via the UI for a clean removal.)

Citing

If you use this in your work, please cite it (use the "Cite this repository" button on GitHub, or):

@misc{a0gitnexusplugin2026,
  title        = {a0-gitnexus-plugin: GitNexus code-graph for Agent Zero},
  author       = {King0James0},
  year         = {2026},
  howpublished = {\url{https://github.com/King0James0/a0-gitnexus-plugin}},
  note         = {GitHub repository}
}

License

MIT — see LICENSE.