vivac
A tree where every node knows which node it was born from. It exists to answer "why are we here?" months later, when nobody remembers any more.
$ vivac why 11
Why we are here -> t11
------------------------------------------------------------------
g1 vivac 0.1 publishable
A provenance system for work that can answer "why are we
here" months later.
(7 open / 4 closed below)
|
v
t8 Port to Rust in the public repo
When the format stops moving, not before.
(3 open below)
|
v
t11 Redaction guard on write
Security pillar. Goes BEFORE any cloud mode.
^^^ you are here
In parallel, still open (2):
t9 Web interface for the maintainer
t10 Migrate from JSON to SQLite
t8 does not close until these close (1):
t11 Redaction guard on write
The problem
When you develop with an agentic AI, work spawns more work. Three hops in, you have lost the thread of what you originally set out to do.
It is not a memory problem: usually everything is written down. It is a provenance problem. What is written does not say what it was born from, and without that edge there is no way to reconstruct why you are where you are.
Measured on a real compiler: the path between the goal and the day's work was six levels deep, spread across a chronologically ordered 8,853-line tracker, 52 planning documents and 21 issues. The structure was temporal, which is exactly the opposite of provenance.
Logbooks, ADRs, issue trackers and session memory for agents all store the node. None of them stores the edge. That is how you can have everything written down and still not be able to say where something came from.
Where it sits works through that category by category, and says where each of them is better than this.
How it is used
There are two audiences, and the tool splits in two because of them.
The agent writes. Capture hangs off the seams of the work: you open a node when you start, you close it when you finish. The provenance edge is created on its own, with nobody having to remember to declare it.
The maintainer reads.
;
Everything the agent needs to do can be done from the command line, with no
interface in the way, and every one of those reads takes --json — every one
but the brief, which is written to be injected into a session and read as
prose, never parsed.
And the maintainer looks. vivac web draws the tree in a browser, on this
machine and nowhere else: a server somebody starts and that dies when they
close it, bound to 127.0.0.1, reachable through a one-time key it prints.
It has no functions of its own. Every page calls the same function the command calls, so there is no second write path for the redaction guard to be walked around, and anything that goes wrong on a page has a command that repeats it. If a page needs something the command line does not have, that thing gets built on the command line first.
Today it serves one page: what moved while you were not looking. It is there
because a context budget and a screen are not the same problem. The brief
answers where am I in a few hundred tokens and does it well; it was never
going to answer what changed under me while I was not asking.
And there are safe stops. A vivac is the bivouac partway up a climb: a
coherent state, with the stack frozen and the identity of the code at that
moment. push, pop and park leave one without anybody asking.
restore never touches the working tree. Mixing context navigation with
tree manipulation gives you a branch manager worse than git.
The two edges
It is the distinction that holds the model up, and it came out of seeding two real trees and putting them side by side:
| Question it answers | When it is created | |
|---|---|---|
| born from | where did this come from? | on its own, at every push |
--blocks |
does this stop its parent from closing? | explicitly |
A closed batch of issues with an open finding underneath is correct: the
batch finished and the finding is another thing. An audit marked DONE with
its findings open is a false marker — one of those took 26 days to be
spotted. Same shape, opposite verdict.
That is why vivac done refuses to close with open conditions and lists
what is missing. It is the only rule in the model that rejects an operation,
and it earns that privilege because the case it prevents is measured.
$ vivac done 8
t8 CANNOT close: 1 open closure condition(s)
t11 Redaction guard on write
A run closes with its findings, not with its report.
Closing it anyway leaves a trace: vivac done 8 --force
When a premise turns out false
The two edges above answer where something came from and what stops it from closing. There is a third case, and it is the one that rots a log: an assumption is refuted, and everything built on top of it stays on the page looking exactly as valid as it did the day before.
$ vivac abandon 2 "the bottleneck was I/O, never the parser" --cascade --rescue 4
a2 The parser is the bottleneck -> abandoned
and 1 descendant(s) with it
Rescued, and still born from a2:
f4 The token cache survives the rewrite
Their lineage crosses an abandoned node on purpose: where they
were born does not change because it got discarded.
There is a fair objection to doing any of this, and it is the reason most tools stop at reporting the break instead of acting on it: cutting a link discards intent, and nothing left behind can say what was meant. Once the edge is gone the reader is guessing, and a guess written down as a fact is worse than a gap.
The objection is right about the danger and wrong that the danger is unavoidable, and the whole difference is where the record lives. Intent is lost when the link is the record — remove it and there is nothing left to read. Here the link is not the record. The node is, and it keeps its own reason, its outcome and its parent.
So a rescue does not reparent. f4 still hangs off the assumption that
turned out to be false, because that is where it was born, and being born
somewhere is not undone by that place being wrong. What changes is state, not
lineage.
Which is why "what was meant" is not lost. It is one edge up, and still on the path:
$ vivac why 4
g1 Make the parser faster
profiles pointed at it
|
v
a2 The parser is the bottleneck [abandoned]
measured on one file, never on the corpus
= the bottleneck was I/O, never the parser
|
v
f4 The token cache survives the rewrite
it is independent of why we started
The refuted assumption stays readable, carrying both the reason it was believed and the reason it fell, standing between the goal and the thing that outlived it. Nothing was dropped, so nothing has to be guessed.
What it never stores
A provenance tree is a map of where a system is weak and not yet fixed. That forces a few things, and they are not negotiable:
- No keys and no secrets. There is a redaction guard at write time. In doubt it refuses and says why; it never stores in silence.
- No personal data. No email, no name, no home path. The
actoron every event is an opaque identifier. - No file contents. Only paths, references and prose about what was decided. A write that opens a fenced code block is refused. It bounds the blast radius of a leak to what was being worked on, never to what the code is.
- No telemetry. The binary does not phone home.
These rules come from the pillars, which govern by definition: security vetoes, performance budgets, UX proves a surface is worth reading, DX judges.
Status
Tier 0 complete. The tree, the two edges, the closure rule, the redaction
guard, the brief with its token budget, the session hooks, the vivacs and the
Anchor with its Git and Null implementations. The suite runs on every
pull request, on Linux, macOS and Windows; twelve of its tests are the brief
specification's contract, executed against the real binary.
reconcile is the first of Tier 1. It answers the one question that keeps the
tree honest -- what changed since the tree last looked, and which of it does
no node claim? -- by diffing the anchor's history against the governs globs
the nodes declare. It reports and never writes: it can say nobody claims a
file, and it cannot say which thread that file belongs to.
find is the other half of reading. It returns every node whose title, reason,
note or outcome holds all of the words, newest first, each with the lineage it
hangs from. Closed nodes are included on purpose: what you go looking for
months later is usually finished.
find --everywhere asks the same question of every project this machine has
seen rather than the one you are standing in. It reads the registry, so it
works from anywhere, including a directory with no tree above it at all, and
it groups the answer by project because an alias only means something inside
its own tree. It reads each project's index instead of folding its log, and it
never writes: searching from one project does not touch another's .vivac/.
An alias from another tree is not addressable on its own, so why takes
--project, naming a project by its directory name or by a path. A name that
matches two projects is refused rather than guessed, because answering about
the wrong tree looks exactly like answering about the right one.
The brief is deterministic by contract: same log, same --now, same bytes.
The spine — the path from the root to the focus — is never truncated: if it
does not fit the budget it comes out anyway, and the warning says that what is
left over is tree, not render.
Measured on this machine at ten thousand nodes, 200 calls per cell, p50 / p99 in milliseconds, on a tree with its derived index in place — which is what a tree has after the first read of it. The CLI column starts a fresh process every time and includes the ~8.5 ms that costs; the MCP column is a resident server, which is how an agent calls.
| CLI | MCP | |
|---|---|---|
brief |
16.9 / 23.7 | 1.1 / 2.1 |
why |
17.6 / 23.5 | 3.7 / 5.8 |
open |
19.3 / 25.8 | 14.6 / 19.5 |
find |
17.1 / 23.6 | 7.3 / 10.6 |
tree |
21.7 / 41.3 | not a tool |
A write is p99 1.1 ms at that size, and it does not grow with the tree: over MCP the server appends against the tree it is already holding.
The CLI column used to read worse, and the tool was not. The fixture those numbers came from could never keep a derived index. The index is only written when every id in the log has the shape a real one has, and the generator that built the fixture emitted short ones, so the write declined every time and said nothing about declining. Every call folded the whole log -- the cold path, which a real tree takes once and then stops taking.
Side by side on one machine, one tree, one size, with nothing different but
whether the index could be kept: tree came back 50.7 / 62.8 without it and
22.4 / 29.4 with it. why came back 50.5 / 95.3 against 17.5 / 23.5.
So the reading budget was never being missed. tree was reported at 51.3 at the
tail, a hair over the 50 ms ceiling, and that was enough to open a question about
whether the ceiling was the right one. It was: the number was taken on a tree
that cannot cache. What did come out of chasing it is real and stayed -- most of
the cost that was there was one write syscall per line of output, and the crate
now buffers and flushes once.
Not there yet: team mode.
0.3.0 does not read a log written by 0.1.x or 0.2.x. The tool was written in Spanish and those releases stored the event fields under Spanish names, which 0.2.x read through aliases. 0.3.0 speaks one language, so it reports those lines as unreadable rather than guessing. If you have such a log, 0.2.1 still reads it.
Releases before 0.3.2 could park the wrong node. park <id> "<reason>"
with an id that named nothing exited 0, parked whatever the focus was instead
of what you asked for, and kept the unresolved id as the reason -- dropping the
reason you wrote. The event it leaves behind is indistinguishable from a
deliberate park, so the tree never says it happened. If one of your trees was
written with an earlier release, vivac parked is where to look: an entry
whose reason reads like an id, or a node you do not remember parking.
vivac focus <id> takes it back out and asks no permission to do it, because
parking only ever said "maybe I will be back".
Hooks
SessionStart injects the brief into the agent's context; Stop leaves an
automatic stop. Stop runs on every turn, not at session close — there is
no end-of-session event — so the stop is only saved if the tree changed since
the previous one: a stop that repeats identically is not a stop, it is a log.
Both stay quiet and exit 0 where there is no .vivac/, so they can be left in
the global configuration without getting in the way of other projects.
MCP
The tree as tools an agent can call:
Eleven of them: four reads — vivac_brief, vivac_find, vivac_why,
vivac_open — and seven writes — vivac_push, vivac_pop, vivac_add,
vivac_decide, vivac_note, vivac_park, vivac_save. It speaks JSON-RPC
over standard input and adds no dependency: the server is the binary you
already installed.
Eleven and not more, because every tool costs context in every session the agent ever opens, so the list is a budget and not a catalogue. The seven writes are the seams of the work — opening something, closing it, parking it, noting it, deciding, and the safe stop — and nothing else got in.
The same budget governs what a tool hands back. vivac_open returns each
front as five fields — alias, kind, state, title and lineage — rather than
the whole node, because the answer to what is unfinished is a list of names
and where they hang; vivac_why on an alias brings the rest. It used to
return the node, which over ten thousand nodes meant 1,993,053 bytes where
599,012 will do. A payload nobody asked for costs the same context as a tool
nobody calls.
vivac_find takes everywhere and vivac_why takes project, the same two
questions the command line answers. They arrived together on purpose: a hit
from another tree carries an alias, an alias means nothing outside the tree
that issued it, and finding without being able to open would be half an
answer. What crosses is the project's name, never its path — a path carries
whatever the account and its directories happen to be called, and through a
tool that lands in a model's context. No write tool takes a project: writing
into a tree you are not standing in is a larger permission than reading one,
and nobody has asked for it.
Nothing destructive is reachable from here, and that is deliberate.
abandon discards a node and everything below it, and through a tool that
would happen without anybody seeing a command. It stays on the command line,
where somebody is looking. So do the operations that reshape a tree rather
than record work — closing another node, blocking, flagging, restoring a
safe point. Those belong to whoever maintains the tree, and they have a
terminal.
The writes are here because the command line cannot be where an agent writes. Starting the process is 8.2 ms at the median, more than the whole 5 ms budget the performance pillar sets for writing a node, and no process design brings that down.
Over MCP the server folds the tree once and keeps it, so a write is an append against a tree that is already there: 1.1 ms at p99 over ten thousand nodes, and flat in the size of the tree, because what used to grow with it was the fold. A read straight after a write no longer pays for a second one either.
That correctness rests on a staleness check, not on trust: if another process wrote to the log, the tree is folded again before the operation. Eight tests assert that what the server holds after a write equals a fresh fold of the log, because a fast write that quietly drifts from the record would be worse than a slow one.
Hooks and MCP are not the same offer, and the difference matters. A hook fires
whether or not anybody wanted it; a tool is called only if the agent decides to.
So the brief still arrives through SessionStart, where nothing has to choose
it — vivac_brief is for asking again mid-session, not for the opening.
On Windows, stop the server before updating. A running vivac mcp holds
the executable open, so cargo install vivac cannot replace it and fails with
an access-denied error — os error 5 — that names neither MCP nor this
command, and so does not lead back to the cause. Close the session that
started the server, then install. Linux and macOS replace a running binary
without complaining, so this one is Windows only.
Install
From source, cargo install --path . inside the repo.
No background process, and no network in the write path — push is the binary
writing to a file. The binary never phones home, and that one is a promise
rather than a description of the current version. The store is .vivac/,
three files: the log, the config, and a derived index that can be deleted
without changing any command's output.
There is a second place, and it is the only thing this binary puts in your
home directory: ~/.vivac/, one per machine, holding a registry of the trees
the machine has seen. A project enters it by being used — every command
already knows the root it is standing in, so registering it is an effect of
the work rather than a step to remember, and nothing goes looking through your
disk. Entries are keyed by the id of each project's first event, so moving a
directory reads as the same project at a new path instead of a second one.
VIVAC_HOME points the whole thing elsewhere.
The search that finds a project walks up looking for a .vivac/, and this
is one, so it skips it: a directory under your home with no project above it
refuses rather than resolving to your home. What it skips is recognised by
holding the registry, not by sitting at a particular path, which is what
keeps the rule true once VIVAC_HOME has moved the store.
It holds absolute paths and it stays here. Nothing sends it anywhere, and it lives outside every project, so no repository carries it off by accident. Deleting it costs you the list until each tree is next used, and costs no tree anything at all.
Getting it all out
vivac tree --json prints the whole tree: every node with its reason, its
note, its outcome, what it refers to and what it governs. It is not the
filtered view tree shows a person — the JSON ignores --all and carries the
closed and the parked as well, because an export that quietly drops what
finished is not one.
The log underneath, .vivac/events, is plain JSON lines and nothing stops you
reading it. What is not written down anywhere is what a line means, and that is
on purpose rather than an oversight: the format is still moving, which is what
keeps 1.0 away, and documenting it as a promise is how it would stop being
able to move.
Versioning
The project is in 0.x, and while it is, the minor is the position that
breaks: 0.3.x to 0.4.0 may change a public surface, and a patch never
does. The rule has already been spent once — 0.3.0 stopped reading the logs
0.1.x and 0.2.x wrote, and went out as a minor for that reason.
The format on disk is not settled either, and that is what keeps 1.0
away. It was going to settle by moving into SQLite; the measurement rejected
that, and docs/PILLARS.md records the reversal where the
doctrine lives. What is left is smaller than a migration and still open: the
read cost turned out to sit in how a node is built rather than in where its
bytes are stored, and that is not something a 1.0 should promise stability
across before it is answered. 1.0 comes after the store settles.
Contributing
Not for now — neither pull requests nor issues. The reason is in
CONTRIBUTING.md.
Licence
MIT OR Apache-2.0, at the option of whoever uses it. The text of each is in
LICENSE-MIT and LICENSE-APACHE.