AI Synthesis

journal synth reads your notes and generates curated summaries — weekly digests, daily rollups, decision histories, stale project alerts — using a language model of your choice. It never runs automatically; you invoke it when you want it.

The basics

journal synth weekly         # preview: prints the prompt and output path, no API call
journal synth weekly --write # actually generates and saves the output

By default, synthesis is a dry run: it shows you the prompt it would send and the file it would write, but doesn't call any API. Add --write when you're ready.

Output files land in reflections/ in your journal repo (e.g. reflections/2026-W24.md). Existing files are never overwritten — journal adds a -2, -3, etc. suffix if one already exists.

Synthesis kinds

Command	What it generates
`journal synth weekly`	A summary of your ISO week's notes → `reflections/YYYY-Www.md`
`journal synth daily`	Today's notes at a glance → `reflections/daily-YYYY-MM-DD.md`
`journal synth daily --date 2026-06-02`	A specific day
`journal synth meetings`	Digest of recent meeting transcripts (last 7 days by default)
`journal synth decisions --project acme`	A rollup of `@decision` notes for a project
`journal synth stale --days 21`	Surface threads you haven't touched in 3 weeks

Choosing a provider

You have three options, set in .journal/config.yaml:

Cloud Claude (default)

synth_provider: anthropic
synth_model: claude-sonnet-4-6

Requires an Anthropic API key in ANTHROPIC_API_KEY. Best quality for long-form synthesis and voice-matching. Your note excerpts are sent to Anthropic's API.

OpenAI-compatible (OpenRouter, Groq, etc.)

synth_provider: openai
synth_openai_base_url: https://openrouter.ai/api/v1
synth_openai_model: google/gemma-3-27b-it:free

Requires an API key in OPENAI_API_KEY. This is the middle path: capable cloud synthesis without a Claude bill. Free models are available on OpenRouter.

Local Ollama (fully offline)

synth_provider: ollama
synth_ollama_model: gemma4:12b

No API key, no data leaving your machine. For daily summaries and decision rollups, the quality is close to cloud Claude. For long-form weekly digests where voice matters a lot, cloud models have the edge — but for many workflows, local is excellent.

Pull the model first: ollama pull gemma4:12b

Scheduling synthesis

Run journal synth daily --write on a schedule to get automatic daily digests. Add it to cron (at, say, 11:55 PM):

55 23 * * * /usr/local/bin/journal synth daily --write >> ~/.journal-synth.log 2>&1

Or use launchd (macOS) / systemd timers (Linux) — the same patterns as the index watcher. See Configuration Reference for details.

Writing in your voice

If you create a file at docs/VOICE_PROFILE.md in your journal repo, journal reads it at synthesis time and injects it as a style reference. The model uses it to match your vocabulary, tone, and any phrases you want to avoid.

journal init creates a starter template at docs/VOICE_PROFILE.example.md — copy it, make it yours, and your digests will start sounding more like you over time.

The profile is plain Markdown. Evolve it whenever you notice the output drifting from your style.