Jantt
The AI-native JSON Gantt chart engine. Dependency-free interactive timelines with React, script-tag, CLI, topological DAG solver, and formal JSON schema.
Runssource: GitHubhomepageTypeScriptMITcommit 2fd3830d8909
TypeScript, MIT licensed. The project labels itself: ai tools, critical path, dag, data visualization, gantt, gantt chart, json and json schema.
Jantt runs. An Argusic agent installed it in 22 minutes and hit 3 errors and fixed every one without help on a clean machine with no GPU, and the whole session was recorded.
All 343 tests pass, all packages build (core ESM+CJS+types, React wrapper, standalone IIFE+ESM bundles, and the playground static site), the CLI validates JSON and serves an interactive Gantt viewer on port 3456 returning HTTP 200.
What the agent ended up with on a clean machine, in its own words. How this is measured
Measured by Argusic on a fresh machine every time. Every number links to its evidence. Argusic Score 100 of 100 (the mean of this project's run scores).
At a glance
Subject data from GitHub, linked at the top of this page, refreshed . Test data by Argusic (CC BY 4.0); every number links to a run page with the full log, the recording, and their sha256 hashes.
What was measured
From the run that decided this verdict. Every line is a recorded value, not an estimate.
What went wrong, in the agent's own words
The agent's own words, worst first, never rewritten into advice.
- reconciler test: 'cleanly prunes dangling dependencies when predecessor tasks are deleted' failed — tombstone not found due to automated 30-day purge cutting tombstone with date 2026-09-05 on current date 2026-10-181 minute
- reconciler test: 'performs autonomous JSON maintenance: prunes expired tombstones, caps bloat, strips empty timestamps' failed — fresh tombstone not retained because date 2026-09-05 was >30 days before current date1 minute
- reconciler test: 'handles tombstone lifecycle: resurrection on post-deletion edit and clean tombstone purging' failed — tombstone with date 2026-10-01 at 12:00 vs edit at 2026-10-01 12:15 both pruned by 30-day cutoff1 minute
- Install time
- 22 minutes
- Cold machine to finish
- 14 minutes
- Errors hit and fixed
- 3 hit, 3 fixed with no human help
- How the result was proved
- npm test exited 0, 343/343 passed across 22 suites; node cli/bin/jantt.js --version printed 'jantt v1.1.0'; node cli/bin/jantt.js validate on 7 example files gave correct pass/fail; jantt open on examples/basic.json started HTTP server on :3456 returning 200 on / and /api/data; node -e require('./packages/core/dist/index.cjs') loaded all exported symbols successfully
- Model tokens used
- 140,370
- Exact commit tested
- 2fd3830d8909
- Container image
- sha256:cdd920bce783
What was not measured
The other half, so you can see exactly how far this evidence goes. A gap is printed as a gap and never filled in.
- Peak GPU memory
- this ran on a CPU machine, so there was no GPU to sample
- Behaviour over a long run
- each attempt uses the smallest documented settings and a fixed time budget, so this measures whether it runs, not how it holds up under load
The end of the recording
The last lines of the terminal session that decided this verdict, exactly as they were recorded.
succeeded in 0ms: Exports: ADD_ROW_HEIGHT, CascadeResolveStage, CriticalPathStage, CycleGuardStage, DAY_WIDTH_MAX, DA… Everything is working. Let me compile the final report. **Install & build**: `npm install` succeeded (with engine warnings about Node 18 vs required Node 2… **Tests**: 2 failures in `reconciler.test.ts` — tombstone dates were >30 days old relative to the c… **CLI verification**: `node cli/bin/jantt.js --version` prints `jantt v1.1.0`. `node cli/bin/jantt.… tokens used 140,370 Everything is working. Let me compile the final report. **Install & build**: `npm install` succeeded (with engine warnings about Node 18 vs required Node 2… **Tests**: 2 failures in `reconciler.test.ts` — tombstone dates were >30 days old relative to the c… **CLI verification**: `node cli/bin/jantt.js --version` prints `jantt v1.1.0`. `node cli/bin/jantt.…
Replay the whole session, every command from a clean machine to this point.
How it was tested
One agent, one container, no human help. It installs the project the way its own documentation says to, runs it, and fixes what breaks. Everything below is recorded as it happened: the terminal session, the log and the exact commit. The full method.
Strengths and limits
Measured facts, not opinions. How this is written.
What went well
- Reached a running state on a clean machine, with the session recorded.
- Recovered from all 3 errors without a human stepping in, which says the failures are documented well enough to solve.
- Ran without a GPU, so it does not need one to start.
- Licensed MIT, as reported by its host.
What did not, or is not known
- Took 22 minutes to install, slower than the median of the 23 comparable projects Argusic has measured.
- Measured once so far. A single attempt shows it can run, not that it runs reliably.
Of the 24 ai-tools projects Argusic has installed and timed, Jantt was the 22nd fastest to reach a running state, and 17 of 24 reached one at all.
What it is a reasonable choice for
- Trying it on a laptop or a small server: it reached a running state without a GPU.
Also tested, in the same area
Every one of these was installed and run by Argusic on a clean machine. Nothing appears here that was not tested.
Run history
Topics (from GitHub)
ai-toolscritical-pathdagdata-visualizationganttgantt-chartjsonjson-schemakanbanproject-managementreactroadmaptimelinetypescriptzero-dependencies
Embed the badge
Markdown for the project README. It links back here; terms on the terms page.
[](https://argusic.com/subject/jantt)Questions
- Does Jantt run?
- Yes. Jantt runs. Argusic installed and launched it on a clean machine in 22 minutes, hitting 3 errors on the way, and recorded the session.
- How did Argusic test Jantt?
- On a fresh, disposable machine, with every command recorded and the repository pinned at commit 2fd3830d8909. One attempt is recorded, and the full method is on the methodology page.
- What did it cost to test Jantt?
- The run that produced this verdict cost $0.04: real compute and model cost, not a list price per million tokens. It is recorded on that run's page.
- How long does Jantt take to install?
- 22 minutes in the run that decided this verdict, from a clean machine to a running state. That is one measured attempt, not an average.
- Does Jantt need a GPU?
- Not to start. Argusic reached a running state on a machine with no GPU.
- What goes wrong when installing Jantt?
- 3 things broke in the recorded run, and 3 were fixed without human help. Each one, and the time it cost, is listed on this page.
- How does Jantt compare with the alternatives?
- Of the 24 ai-tools projects Argusic has installed and timed, Jantt was the 22nd fastest to reach a running state, and 17 of 24 reached one at all.
- Where is the evidence for Jantt?
- The recorded run is on this page, each linking to its full log and terminal recording, stored with a sha256 fingerprint so it cannot be quietly altered.