palimpsest

A self-maintaining knowledge base — an AI agent that keeps your Notion (or your Obsidian vault) up to date as you learn. Give it anything: a URL, a YouTube link, a PDF, a spreadsheet, a photographed whiteboard, or a sentence you typed. It works out how that information relates to what you have already written, then makes small, reversible, fully-cited edits to the right pages — rewriting what changed, striking what is no longer true, and recording what it disagrees with rather than quietly picking a winner.

A palimpsest is a manuscript written over an earlier text, where the earlier writing is still visible underneath. That is the product: your notes get rewritten as you learn, and every earlier layer stays readable.

Try it in thirty seconds

No account, no API key, nothing of yours writable:

pip install "palimpsest-notion[serve]"
palimpsest demo

That opens a sample knowledge base of eight pages and the real app pointed at it. Paste one of the four suggested facts and watch what happens: one of them argues with a page, one sharpens a sentence that was vague, one needs a page that does not exist yet, one has to choose between two pages that both want it. Then open the Activity tab and undo any of it.

Nothing there is faked. It is the ordinary pipeline — same retrieval, same classifier, same planner, same single write door, same undo — with the pages stored as markdown in a temporary folder instead of in your workspace. It uses whatever model you have configured, falls back to a local Ollama if you have one, and if it finds neither it still opens and says so.

Here is what the first of those four produces. The source says per-parameter clipping is better; the page says the opposite. It does not pick a winner. It shows you both, says why they cannot both be true, and waits — which is the one thing it will not do without you, at any autonomy setting:

Everything else is applied, and every applied change has an Undo next to it.

Then point it at your own notes

Install the app — latest release for Windows, macOS or Linux — and open it. A short wizard asks for your model and Notion keys, checks each one on the spot, and makes the single Notion page it works inside. The Telegram step is optional — skip it and add a bot later from Settings. Answers go to a config file it reads on every later start, so there is nothing to edit by hand.

Then drop something on the window and watch what it proposes.

There are three surfaces, and they are three surfaces on purpose:

All three talk to the same local service, so there is one database, one config file and one set of keys however you came in. Prefer a terminal? Everything is also a command:

pip install "palimpsest-notion[all]"
palimpsest serve

Two backends. Notion is the one this was built for. The other is a folder of markdown files — an Obsidian vault, a git repo, anything you can open with cat:

PALIMPSEST_BACKEND=markdown PALIMPSEST_VAULT=~/vault palimpsest serve

In the app, the same two settings live under Settings → Or a folder of markdown files. Same pipeline, same guarantees. See Where your notes live.

palimpsest setup                      # re-run the wizard any time
palimpsest eval retrieval             # can it find the right page? no key needed
palimpsest eval component             # how good is the classifier, on your model
palimpsest agent "what did I write about attention?"
palimpsest sync                       # mirror your Notion locally
palimpsest sweep duplicates           # what you already wrote twice (no model needed)
palimpsest apply pch_… --reviewer sk  # the only command that writes
palimpsest undo pch_…                 # exactly reversible

The problem

You study something and write it up in Notion. Two weeks later you learn more about the same topic, and now you have to remember which pages touch it, open each one, decide whether it needs changing, perform the merge without contradicting what past-you wrote, and remember where it came from.

The deciding step is the one that breaks. It is genuinely ambiguous, it is boring, and there is always an escape hatch — make a new page. Take it fifty times and your knowledge base is four versions of the same topic, none authoritative.

The reframe

Everyone who builds this builds "embed the new text, find similar pages, ask a model to rewrite them." That tool gets abandoned in a week, because rewriting a page is an unbounded operation and you cannot review unbounded operations.

The atom here is not a document. It is a claim. And the question is not "update or create" — it is how does this claim relate to what I already wrote?

Three consequences fall out of that table, and they are the whole design:

corroborates is why the base stops bloating. Most "new information" about a topic you already studied is not new — it is the same claim from a different source. Under any other design that becomes a new paragraph. Here it becomes one small grey marker on a sentence you already wrote, and no prose is added at all.

contradicts is the safety property everything rests on. A knowledge base that silently replaces a true claim with a false one is strictly worse than no automation, because you stop knowing which parts to trust. So the system never decides which of two sourced claims is true — not at any setting. What the top autonomy level adds is the recording of a disagreement: the competing claim written directly beneath the line it argues with, both sources cited, the original sentence untouched. One append, one inverse, one tap to undo. Deciding stays yours.

Every edit is typed, small, and exactly reversible. add_citation, update_text, insert_footnote, strike_block, archive_block, create_page, link_pages, move_page, rename_page, set_icon, set_cover, rewrite_section. There is no delete: the Notion client has no DELETE verb at all, and the most destructive thing in the vocabulary is a strike-through, which leaves the words on the page.

rewrite_section is the one that is not small. It replaces a run of blocks wholesale — headings, prose, callouts, code, images, columns — because a knowledge base worth reading needs sections restructured, and no amount of sentence-level editing produces that. It gives up reviewability-at-a-glance and keeps recoverability: the blocks it replaces are snapshotted first, so undo restores them exactly, in order. Those are two properties, not one, and only the first is traded away.

What it does on day one, before it writes anything

palimpsest sync pulls your workspace into a local mirror. Then, with no model and no API key at all:

palimpsest sweep duplicates    # the same content on two different pages
palimpsest sweep questions     # what your base knows it doesn't know
palimpsest sweep stale         # claims that have outlived their topic's half-life

sweep duplicates is the one to run first. It is the accumulated damage of the last two years, listed, ranked by similarity, with a suggested merge for each pair. It reads the mirror and changes nothing.

With a model key you also get sweep contradictions — not new-versus-old, but old-versus-old: places where your notes disagree with themselves. Your Notion almost certainly contains some right now, and you do not know which.

Architecture

capture → normalise → extract claims → retrieve → classify relation
        → plan patch → review → apply → record provenance
                          ↑                    │
                          └──── learns from ───┘

Anchors, and why citations don't rot

Every adapter emits segments — spans of normalised text with a citable locator. A PDF anchors to p. 14. A YouTube transcript anchors to 1:42:07 and the footnote links to that second of the video. A spreadsheet anchors to Sheet1!A–D47.

The extractor maps each claim's character span back to its segment, and the original bytes are archived on the way in. So a footnote still resolves in two years when the page 404s. This is the part comparable tools skip, and skipping it is why their citations are decoration.

The mirror is not a cache

Notion's API has no diff primitive, no transactions, and no usable version history. So exact undo, "which source produced this sentence", and time travel are properties of our ledger, not of Notion:

palimpsest history <page_id>        # every applied change, newest first
palimpsest provenance <block_id>    # source, claim, anchor, who approved it
palimpsest undo <patch_id>          # exact reverse, including partial patches

Safety model

Two independent switches, because the failure they prevent is unrecoverable:

PALIMPSEST_APPLY=0          # default. Nothing is ever written.
PALIMPSEST_AUTONOMY=none    # none | low | medium | full | everything

autonomy names the highest risk tier that may apply without review. low covers new and corroborates. medium adds refines, supersedes, duplicate and extends. full is every tier that is automatable at all.

everything is the only rung that touches a contradiction, and what it does is narrower than it sounds: it records the disagreement in a callout directly beneath the line it argues with, citing both sources. It does not decide which one is true — nothing here ever does, at any setting — and it inverts by removing one block, so a reader who disagrees with the machine loses nothing by undoing it. "May record the argument" and "may settle the argument" are different powers, and only the first is on offer.

How sure the classifier must be scales with what the edit would do: 0.60 for a purely additive block, 0.75 for one that rewrites a sentence, 0.90 for one that changes what an existing sentence means. PALIMPSEST_MIN_CONFIDENCE moves the whole scale.

Beyond that: the applier writes each operation's inverse before running it (Notion has no transactions, so a patch interrupted at operation six must still be reversible), it never hard-deletes (strike-through and restorable trash only), and it stops at the first failure with status partial rather than ploughing on.

None of the above is a promise you have to take on trust. The invariants are pinned by tests/unit/test_safety.py, which runs offline with no key in every CI run, and they are written out in docs/safety.md.

Commands

The filing, not just the prose

A knowledge base decays in two independent ways. The prose drifts — which is what the seven relations fix — and the filing drifts: pages pile up at the top level because creating one there is the path of least resistance, six pages on one subject end up in five places, half of them are called "Notes".

No amount of editing prose fixes that, because the problem is not inside any page. So organise plans the shape, and emits the same kind of object everything else here emits — a patch of small typed operations with exact inverses:

palimpsest organise           # proposes hubs, moves, renames. Writes nothing.
palimpsest apply pch_… --reviewer sk
palimpsest undo pch_…         # the pages go back where they were

move_page, rename_page and set_icon invert from the mirror, which already knows each page's parent, title and icon. There is deliberately no "restructure workspace" operation, for the same reason there is no rewrite_page.

One thing it refuses to do. Notion's move endpoint takes a page or a data source and has no workspace destination, so a page currently at the top level can be filed into a hub but never moved back out by the API. That operation has no inverse, so palimpsest will not perform it — such pages become review items explaining the one-way door instead.

Every change, and why, inside Notion

The ledger that makes undo real lives in SQLite, where you cannot see it. But the question people actually ask — why does this sentence say that, and who decided? — gets asked in Notion, six months later, on a phone. So the ledger is mirrored into two databases under your root page:

palimpsest · Sources is one row per thing you fed it, with how many claims came out and how many edits landed. Filter Changes to every supersedes you ever accepted, or read one page's history without leaving Notion.

The same reasoning also goes into the footnote on the page itself, next to the sentence it explains — because nobody runs palimpsest provenance on a block.

A journal write can never fail an edit: the row goes in after the operation succeeded, and its failure is swallowed. Losing a log line is a nuisance; refusing to edit your notes because the log line failed would be absurd.

The agent

Talk to your notes. The agent turns palimpsest from a pipeline you feed into something you converse with — over Telegram, or from the terminal:

palimpsest agent "what do my notes say about attention scaling?"
palimpsest telegram          # the same agent, on your phone

Two things, and only two:

• Send it anything — a link, a file, a voice note, a thought — and the knowledge base updates.
• Ask it anything — and it answers from your notes, with page citations.

It has a bounded tool surface (search, read, capture, sweep, organise, apply) and it never writes to Notion directly. Every edit goes through one gate: operations within your PALIMPSEST_AUTONOMY setting apply; everything else is held for a tap. The agent cannot raise its own autonomy, cannot force a held edit through, and cannot apply a contradiction — those are locked in code, not just asked for in the prompt, and the guarantees are pinned by tests/unit/test_safety.py, which must pass at 100%.

Measurement, and how autonomy earns its raise:

palimpsest eval bootstrap    # turn your Approve/Reject history into labelled examples
palimpsest eval component    # per-relation precision & recall against that golden set

The golden set is a test set, not training data — nothing is fine-tuned. It grows for free from every approval you make, and it is the number the autonomy ladder is meant to rest on rather than being set by hand.

It writes the page, not a list

Feed it a document about something you have never written about and it does not append eleven bullets in arrival order. The claims go to a composer that lays out a page: an opening that says what the topic is, heading_2s that follow the shape of the material, prose rather than fragments, a callout for the thing that would otherwise be missed, code where code is clearer than a sentence.

One source produces at most one new page. An earlier version folded page creations by title, which fixed the obvious duplication and left a subtler one — a single article about retrieval produced six pages, four of them one sentence long, because every claim carried a different topic string so no two titles ever collided. Same fragmentation, different route, and a reader cannot tell the difference.

Two things are checked before a composition is used, because "lay this out nicely" is a short step from "quietly drop the boring half":

• Every claim must survive. The layout is verified against the claims that went in, and one that dropped any is discarded — the bullets stand instead. A rewrite may change how a page reads; it may not lose a fact.
• The old version is kept. Composition rides on rewrite_section, so the page before is snapshotted and one tap puts it back.

Ask the agent to tidy a page and it uses the same machinery — rewrite_page is a tool it has, gated exactly like the smallest citation.

Where your notes live

Notion is what this was built for and is still the default. But the whole pipeline talks to the workspace through seventeen methods behind a single write door, so a second backend is a second implementation of that interface rather than a fork of anything:

PALIMPSEST_BACKEND=notion                          # the default
PALIMPSEST_BACKEND=markdown PALIMPSEST_VAULT=~/vault

A markdown vault is a folder of .md files with a small YAML header — an Obsidian vault, a git repo, plain files you can grep. Headings, nested lists, to-dos, code, quotes, images, and Obsidian's callout syntax for callouts and toggles all round trip byte for byte, so the tool never rewrites a file it merely read.

The awkward part is block identity. Notion hands out ids; a file has none. So they live in a sidecar under .palimpsest/ and are re-aligned against the file on every read — exact text first, then same-type-nearest-position. Edit a page in Obsidian while this is running and the ids survive, which is what keeps provenance and exact undo true across an edit the tool did not make.

Three things follow from having a second backend, and each matters more than the feature:

• You can try the product without risking your notes. palimpsest demo is this backend pointed at a sample vault.
• The write path is testable offline. Ingest → classify → plan → apply → undo runs end to end in CI with no network and no key. It used to be that the only honest test of a write was against a live workspace, which meant it mostly did not happen.
• Your notes are not hostage to one vendor. A knowledge base you feed for years should outlive the app that maintains it.

What a vault does not have is databases, so the activity ledger is a markdown table instead — which is what a database view is for a reader anyway, and it renders in Obsidian and on GitHub.

Any model, including none of them

The model is configuration, not code. PALIMPSEST_MODEL_BASE_URL points at anything speaking the OpenAI API; otherwise the provider is inferred from whichever key is set. Set PALIMPSEST_MODEL_PROVIDER=ollama and it runs entirely on your machine — no key, no cost, nothing leaving the computer, and free embeddings from the same runtime.

That freedom has a price, and the eval is how you see it rather than discover it. Every model below classified the same twenty labelled cases from the workspace committed at src/palimpsest/evals/data/workspace.json:

palimpsest eval leaderboard --models anthropic/claude-sonnet-5,ollama/qwen3:8b

Local models vary run to run — qwen3:8b has scored anywhere from 0.57 to 0.65 on this set — which is itself worth knowing before you hand one write access.

Contradiction recall is the column to read. A model that misses two contradictions in three is not a model to hand write access to, whatever its headline number, which is why that metric is weighted 3× and checked on its own.

So palimpsest status refuses to be quiet about it: give write access to a model that has never been measured, or one that failed, and it says so and names the command.

palimpsest eval component     # how does *your* model classify?
palimpsest eval retrieval     # can it find the right page? needs no model at all

Embeddings are the opposite story. Local ones are excellent and cost nothing. On the same fixture, mxbai-embed-large through Ollama takes the two cases that share no vocabulary at all with their answer — you wrote "the CKA/RSA stuff", the source says "representational similarity analysis" — from 0% to 100%, and lifts mean reciprocal rank on everything else from 0.96 to 1.00. Vectors are cached in the store by block, text hash and model, so each block is embedded once and an edited one re-embeds by itself.

The honest recommendation, then, is mixed: a good hosted model for the judgement, local embeddings for the search. Fully local works, and the product will tell you what you gave up for it.

The app

The window is the product. Three tabs, and the first one is the whole loop.

Capture. A drop zone that takes files, pasted links, pasted text and dragged selections, above a live feed of everything in flight. The feed is one stream rather than a queue view and a review view, because "what is happening" and "what needs me" are the same question asked half a minute apart. A change waiting on you rises to the top in rubric red — the colour medieval scribes used for exactly what the reader must not skip — and the ones that landed on their own sit below it in aged copper.

Each proposal shows the sentence it wants to write over the top of the struck-through line it replaces, which is the metaphor made literal and also the fastest way to judge an edit: you can see what you are about to lose. Relation, confidence and the model's one-line reasoning are on the card. Approve and Reject are the only two buttons.

Ask. Questions answered from what you have actually written, with the pages cited.

Settings. Keys, grouped by what they buy you and each checked when you paste it, and above them the two switches that decide whether anything reaches Notion at all — in plain language, not as PALIMPSEST_AUTONOMY=medium buried in a list. Contradictions are never applied automatically at any setting, and the panel says so where you set it.

The interface is built once and shipped inside the Python package, and the app is an Electron shell that loads it from the local service. That is why there is no second implementation to drift: the window, the onboarding wizard and anything you reach from a terminal are the same build.

How the app works

It does not bundle Python. On first run it finds the interpreter you already have, builds a virtualenv under its own data directory, and installs palimpsest-notion into it — which keeps the download small and means the engine upgrades without reinstalling the shell. If a palimpsest serve is already running on the port, it adopts that rather than fighting it.

It adds the one thing a tab cannot: a global capture shortcut, which opens a small box over whatever you are doing. Drop a file, paste a link, press Enter — the box is gone before the ingest starts, because the queue outlives the window. Ctrl+Shift+Space if it is free, and it tries three more if something else owns it; the tray menu always names the one that took.

cd clients/desktop && npm install && npm run dist   # build the installer yourself

On Windows without developer mode, add -c.win.signAndEditExecutable=false: the signing toolchain unpacks symlinks Windows will not create unprivileged. CI builds all three platforms on tag.

Your phone, and the page you are reading

The other two surfaces, both thin wrappers over the same queue.

Telegram puts capture and approval on your phone. Send the bot a link, a PDF, a voice note, a screenshot or a paragraph; minutes later it tells you what changed — how many citations it added on its own, and what it wants you to decide, with the reasoning and Apply/Reject buttons.

An allowlist is mandatory: a bot token is a bearer credential, so an unpaired chat is refused. Pairing is done from Settings, where the backend watches for your next message while you are looking at the screen. The bot never accepts an unattended first-message-wins pairing, because that is a race anyone can win by finding your bot before you do.

The extension is attached to every release as palimpsest-extension-<version>.zip. Unzip it, open chrome://extensions, turn on developer mode and drag the folder in. It is not on the Chrome Web Store, so this is the install — which is honest about what it is rather than asking you to clone a repository.

palimpsest telegram                  # or just `palimpsest serve`, which starts it too
npm --prefix clients run pack:extension   # build the zip yourself

The extension sends a YouTube link (the server fetches better captions than a page scrape would), reads the transcript off the page on Udemy and Coursera where the server cannot log in, and sends the URL everywhere else. See clients/README.md.

Every surface posts to POST /v1/jobs rather than /v1/ingest, because ingestion takes minutes and a popup does not live that long. The queue is durable, so a capture interrupted by a crash is re-queued rather than lost.

Configuration

Nothing is required to look; two keys are required to be useful. See .env.example for the full list.

Deploying

docker compose -f deploy/docker-compose.yml up for the local stack against Supabase, or deploy/terraform for ECS Fargate + ALB + S3 + Secrets Manager in ap-south-1. See docs/deployment.md.

Documentation

• docs/safety.md — every limit the system places on itself, and the test that enforces it
• docs/design.md — what was chosen and what was rejected: the claim atom, the seven relations, why the inverse is written first, why BM25 rather than embeddings by default
• docs/decisions/ — architecture decision records
• docs/agent.md — how the agent, its tools and the approval gate fit together
• docs/deployment.md — running it as a service
• docs/roadmap.md — what is not built yet, and known limitations
• CHANGELOG.md — what changed in each release

Contributing

See CONTRIBUTING.md. Security reports go through private disclosure, not public issues.

Licence

Apache-2.0.