# onetaskgraph
One interface over the ticketing systems your work actually lives in.
Every image in this README is a real capture of this CLI's output, produced by running the
binary against a small fixture and refused by CI the moment its bytes stop matching what
the binary prints — so the pictures cannot drift away from the tool.
Tasks, projects, labels and the dependencies between them are spread across Linear, GitHub
Projects and a folder of Markdown files, and every tool that wants to reach them ends up
reimplementing all three. `onetaskgraph` implements them once, behind a single query
surface: a command-line tool, the Rust engine crate's library API, and SDKs for Python and
TypeScript. Every consumer reaches the same engine, so their query semantics cannot drift.
Two properties make it different from a lowest-common-denominator wrapper:
- **A rich source is not reduced to a poor one's floor.** Each source declares what it can
do natively. The engine pushes those predicates down and compensates in memory for the
rest — and every response carries the plan it ran, so `--explain` shows you which source
filtered server-side and which one the engine narrowed for.
- **Nothing of your work is kept outside the system that owns it.** No cache, no index,
no local mirror. The engine holds at most one source page at a time and writes nothing
down — enforced by a supply-chain gate that refuses every embedded store and cache
crate, a sandboxed journey that fails if any file written during a run contains your
data, and an assertion that the same query asked twice reaches the source twice.
`copy` is not an exception to that, and the difference is worth stating plainly. A
destination write is at your explicit request, names its destination, goes through that
source's own write interface into that source's own store, and is never read back to
answer a query. A cache is a write nobody asked for that the engine reads back. Copying
a task into a folder of Markdown puts it in the plugin that now owns it; nothing is
kept anywhere else, and the sandboxed journey above drives `copy` and fails, naming the
path, if any file outside that destination's own store changes.
> **Status.** The plugin contract, the workspace, the gate, the configuration layer and the
> query engine are in place, and the binary answers every verb below. The three sources
> this product ships for your work — `local-md`, `linear` and `github-projects` — can all
> be read and written; none is read-only. A copy can still refuse a configured destination
> with no write side, such as a subprocess source whose capability handshake declares no
> writes, but that is a property of that configured source rather than of these plugins.
## Using it
Each source says what it can do, and `sources list` is where you read that back: the
predicates it applies itself, how far it walks dependencies, and the largest page it will
serve.
```bash
onetaskgraph sources list
onetaskgraph sources fields <SOURCE> [--apply] [--json]
# Without --apply this only reports what a GitHub Projects board lacks of the fields its
# source's configuration names: the Status options status_mapping resolves to, and the
# Priority field and its options when priority_mapping is set. --apply adds the missing
# options and creates a missing Priority field, sending every existing option back with its
# id, then verifies every pre-existing option and every item's values of both fields and
# prints recovery data if GitHub drifted.
onetaskgraph sources status-options <SOURCE> [--apply] [--json]
# The Status-only form of `sources fields`, which supersedes it; kept as it was.
onetaskgraph task list [--source S]... [--label L]... [--not-label L]...
[--status S]... [--priority none|urgent|high|medium|low]...
[--project P | --no-project]
[--search TEXT] [--in title|content|both]
[--limit N] [--page TOKEN] [--explain] [--allow-partial] [--json]
onetaskgraph task show <ID>
onetaskgraph task deps <ID> [--direction depends-on|depended-on-by]
onetaskgraph task copy <ID>... --to <SOURCE> [--match-by KEY] [--recreate] [--dry-run]
onetaskgraph task comment add <ID> [--body-file PATH] [--author NAME]
onetaskgraph task comment list <ID>
onetaskgraph task comment edit <ID> <COMMENT-ID> [--body-file PATH]
onetaskgraph task comment delete <ID> <COMMENT-ID>
onetaskgraph task status set <ID> draft|backlog|todo|queued|in-progress|done|cancelled|unknown
onetaskgraph task priority set <ID> none|urgent|high|medium|low
onetaskgraph task content set <ID> --file PATH
onetaskgraph task metadata set <ID> <KEY> <VALUE>
onetaskgraph project list / show / deps # the same flags, minus the project filter
onetaskgraph project copy <ID> --to <SOURCE> [--no-tasks | --member TASK-ID...]
[--match-by KEY] [--recreate] [--dry-run]
onetaskgraph project metadata set <ID> <KEY> <VALUE>
onetaskgraph document list / show # the same flags, minus --status
onetaskgraph document copy <ID>... --to <SOURCE> [--match-by KEY] [--recreate] [--dry-run]
onetaskgraph document metadata set <ID> <KEY> <VALUE>
onetaskgraph label list [--source S]...
onetaskgraph search <TEXT> [--in ...] [--kind task|project|both]
onetaskgraph config show # every setting and the layer it came from
onetaskgraph schema # the JSON Schema bundle both SDKs use
```
An `<ID>` is qualified: `work:ENG-142`. Repeating `--label` narrows — a second one is a
second requirement — and `--not-label` excludes. `--project` takes a qualified id, which
narrows the query to that project's own source, or a bare native id, which is asked of
every selected source.
A **document** is what lives in a project and is not work — a design note, a runbook, a
page somebody has to read. It carries no status and takes part in no dependency graph, so
`document` has no `--status` filter and no `deps` verb. What it does carry is a
**location**: where a reader can actually open it, as a link (`url …`) or as an absolute
path on the machine its source runs on (`path …`). `task show`, `project show` and
`document show` all print it, and `--json` carries the contract type's own shape —
`{"url": …}` or `{"path": …}` — so a program branches on which key is present. Not every
source has documents; one that says it has none is reported as holding none rather than as
having failed, and a copy naming it is refused before anything is read.
A **comment** is added to a task after the task exists, without rewriting it — evidence
appended to an issue somebody else opened. `task comment add` and `edit` read the body from
`--body-file`, or from standard input when that flag is absent, and never from a word of the
command line, so a body quoting a command never passes through a shell; it is stored and
returned byte for byte, and an empty one is refused. `--author` is for a source that records
what it is given, such as a folder of Markdown; GitHub and Linear record the signed-in
account themselves and refuse it rather than drop it. `task show` prints a task's comments
after its body, and its `--json` carries them as a top-level `comments` list for a source
whose tasks have comments — absent, rather than empty, for one whose tasks have none. A
`task copy`, `project copy` or `document copy` never reads or writes a comment at either end.
A task's **status** is set on its own with `task status set`, which writes that one field —
title, body, labels, metadata, dependencies and comments stay exactly as they are — and
answers with the status as the source reads it back. `queued` is the category for work
claimed by something that will do it and not yet started, between `todo` (ready, and nothing
has claimed it) and `in-progress`. A folder of Markdown reads the word `queued`; a GitHub
Projects board sends it to its `Queued` column by default, `status_mapping.queued` naming
another; Linear, which has no such state, refuses it by name.
<!-- llmlint: ignore[contracts_have_one_source_or_a_drift_gate] This user-facing summary is required to describe the GitHub projection; the loopback plugin tests and shared live journey drive the resolved mapping, mutations, and observed read-back together. -->
On GitHub Projects, terminal writes keep both GitHub representations aligned: `done`
selects the mapped `Done` option and closes the issue as completed, while `cancelled`
selects the mapped `Cancelled` option and closes it as not planned. Those are the shipped
option names. An open-category write reopens a closed issue before selecting its mapped
option; a draft item has no issue state to reopen. If any mapped option is absent, the
write is refused by that option's name before either representation changes —
`sources fields` (and its Status-only form, `sources status-options`) counts a terminal
category's mapped option as configured, so it names a missing `Done` or `Cancelled` and
`--apply` adds it. Reads keep
GitHub's issue decision authoritative for closed issues—completed reads `done` and not
planned reads `cancelled`, regardless of the displayed option—while the Status option
decides an open issue's category.
A task's **priority** is one of `none`, `urgent`, `high`, `medium` and `low`, and every task
carries one — `none` when none is set, and for every task of a source that cannot hold one.
`task list --priority` keeps the tasks at any of the priorities named, and `task priority set`
writes that one field and answers with the priority as the source reads it back; `none`
clears it. A copy carries a task's priority like its status. A folder of Markdown holds it as
a `priority:` key, Linear as its own issue priority, and a GitHub Projects board as the
option of a single-select `Priority` field that the source's `priority_mapping` names —
`Urgent`, `High`, `Medium` and `Low` unless it says otherwise. A board source configured
without `priority_mapping` holds no priority, and a copy or a `task priority set` that would
write one to it is refused by name before the board is asked anything. `sources fields
<SOURCE> --apply` creates the board's `Priority` field, or adds the options it lacks, without
disturbing an option or an item's value that is already there.
A task's **content** is replaced on its own with `task content set <ID> --file PATH`: the
file's bytes become the task's body, and status, priority, metadata, labels, repositories and
dependencies stay exactly as they are — on a GitHub board, whose metadata lives in the issue
body beside the content, that block is kept as it was. There is no compare-and-set: what the
file holds replaces whatever the task held.
One **metadata** key of a task, a project or a document is set on its own with `task`,
`project` or `document metadata set <ID> <KEY> <VALUE>`, which adds the key or replaces what
it holds and changes nothing else about the record — every other key, and every other field,
stays exactly as it was, and a key already holding the value is not written at all. `KEY` is
your own dotted `<namespace>.<name>`: two or more non-empty segments, never in the
`onetaskgraph.` namespace this product keeps in step itself. `VALUE` is exactly one JSON
value, parsed as JSON and never as YAML, so a bare `yes` or `2026-01-01` is refused rather
than given a type — quote a string as `'"text"'`. An unqualified id, a key or a value of
those shapes is refused before any source is asked. The answer — `MetadataSet` under
`--json` — carries the id, the key, the value as the source reads it back after the write,
and the record's location. Metadata is not status, so no task it delivers is re-evaluated.
A folder of Markdown edits the one entry of its `metadata:` block and no other byte, and
refuses by name a block it cannot edit that narrowly; a GitHub Projects board sends one
update of the issue body that changes only its metadata slot; the in-memory source holds the
value for the life of its process; and Linear, which has nowhere to put one key on its own,
refuses with `the linear plugin cannot write a task's metadata on its own`. A source with no
write side, a record the source does not hold, and a stdio plugin whose handshake does not
declare the write are each refused by name.
A task can name the tasks it **delivers**: finishing it finishes them. In a folder of
Markdown that is a `delivers:` list in the front matter — a bare id names a task of the same
folder and `<source>:<id>` a task anywhere — and on a GitHub board it is the
`onetaskgraph.delivers` key of the issue's metadata block. The delivered task's
`delivered_by` is onetaskgraph's to keep. Whenever it writes a task that delivers anything,
or delivered something before — a copy, or `task status set` — each delivered task gains the
deliverer's qualified id, a task it dropped loses it, and the delivered task's status follows
its deliverers while it is at `todo`, `queued` or `in-progress`: `in-progress` while any runs,
`queued` while any is queued, `done` once every one is done or cancelled and at least one is
done, and `todo` when they release it. A delivered task at `draft`, `backlog`, `unknown`,
`done` or `cancelled` is left alone, a deliverer its source no longer holds is dropped from
`delivered_by`, and a delivered task that cannot be read or written is reported failed while
the deliverer's own write stands.
A copy rewrites a `delivers` entry naming another item it copies to that item's new id,
counts those under `delivers_rewritten`, and never carries `delivered_by`. Every verb that
writes a deliverer reports each delivered task it evaluated under `delivered`. A `--dry-run`
copy writes nothing and so keeps no delivered task in step: its `delivered` list is empty,
which says nothing about whether a delivered task would have moved.
How a source *spells* a document is its own business. A GitHub Projects board has no
document type, so `github-projects` reads one as an ordinary issue whose title begins
`DESIGN: ` — the title you see has that prefix taken off, and writing a document puts it
back, so a design note copied out of a board and back returns the title it started with.
`docs/metadata.md` records the whole of that rule.
### Seeing which plan you got
`--explain` renders the plan the query ran, per source. Here one `--label` query reaches
two sources of differing capability — a folder of Markdown, and a source that declares it
cannot filter by label at all:
The folder filtered the rows itself; the other source returned the wider set and the engine
narrowed it. One query, two plans, and the same correct answer either way — which is what
the capability declaration above buys you and why it is worth reading. `--json` carries the
same plan as a field, so a script does not have to parse the prose.
### Writing tasks: Markdown in, ticket out
Authoring against a ticketing API is not something a person or an agent does well, and a
folder of Markdown files is. So that is how work is created here: write the files, read
them back through the CLI to be sure they parse, then copy them where your team works.
With `notes` configured as a `local-md` source rooted at `./notes`, create its task folder
and write `notes/tasks/rate-limit.md`:
```markdown
---
title: Rate-limit the sync loop
status: Todo
labels: [{id: local-reliability, name: reliability}]
metadata: {onepipeline.turn_budget: 12}
repositories: [github.com/acme/sync]
---
Back off when the API asks us to slow down.
```
Read it through the CLI before writing to the permanent `linear` destination, then copy
the qualified id the read returned:
```console
$ onetaskgraph task list --source notes
notes:rate-limit todo Rate-limit the sync loop
$ onetaskgraph task copy notes:rate-limit --to linear
```
The read is intentional: a malformed front matter block caught in a local file is cheaper
to fix than a parse failure first discovered while writing to somebody's ticketing system.
Projects use the same flow under `notes/projects/`, followed by `project list` and
`project copy`.
Editing is the same road in reverse — copy out, edit, copy back:
```console
$ onetaskgraph task copy work:T-1 --to notes
$ grep -A2 '^metadata:' notes/tasks/T-1.md
metadata:
onetaskgraph.origin: work:T-1
$ $EDITOR notes/tasks/T-1.md
$ onetaskgraph task copy notes:T-1 --to work
```
The copy back **updates** rather than duplicating because the copied file carries the id
it came from, under the reserved metadata key `onetaskgraph.origin`. Nothing anywhere
holds a mapping: the correspondence lives on the item, inside the plugin that owns it.
Two rules find the counterpart, in this order. If the item's origin names the destination,
that origin *is* the destination item and the copy updates it. Otherwise the destination
is searched for an item whose origin is the id being copied; found, it is updated, and not
found, one is created carrying that origin.
Which rule found it decides what the copy records there. A copy that got its counterpart
from the first rule is a copy **back**: the destination is the original, and the item being
copied is the one that came out of it — so the destination keeps the origin it already
holds, holding none included. Stamping it with the id of its own copy would destroy the
original's provenance, and the next ordinary copy from the store it was authored in would
match nothing and create a second item beside it. Every other copy records the id it was
copied from, which is what makes the next copy of it an update.
| Flag | What it is for |
| --- | --- |
| `--dry-run` | Every read, no write, and the action each item would have got. |
| `--recreate` | An origin naming an item the destination no longer holds refuses by default, because creating there would duplicate work somebody deleted. This says create instead. |
| `--match-by KEY` | Delete or corrupt the origin key and neither rule can find the counterpart, so the next copy back creates a new item. This re-establishes the lost correspondence by matching on `title`, or on a metadata key of your choosing, without hand-editing ids. |
| `--no-tasks` | Copy a project on its own. By default `project copy` copies the project and every task in it, matching each task independently. |
| `--member TASK-ID` | Copy the project and exactly the tasks named, repeating the flag for each, when you know which of them changed. A task not named is not read at the destination, not written and not reported, so a one-task change costs what one task costs rather than a read of the whole project. A named task the destination does not hold yet is still created. An edge to a task not named is written to the destination id that task records at `onetaskgraph.origin`, and a copy whose edge names a task recording none is refused before anything is written, naming that task. A copy naming members was not told about the rest, so it reports nothing `orphaned`. |
`--dry-run` is how you read that table's first row before trusting it: every source is
read, nothing is written, and each item is reported with the action it would have got.
<!-- llmlint: ignore-block[contracts_have_one_source_or_a_drift_gate] Held by the journey
`every_source_kind_can_be_copied_into_a_folder_of_markdown_with_its_fields_intact`,
which asserts the written fields equal and `url` and `key` absent on every copy. -->
Every field a copy read is written — title, content, status, labels, project,
repositories, metadata and the edges — except `url`, `location`, `key`, `created_at` and
`updated_at`, which are the destination's own: the short handle a backend shows people is
issued by that backend, so the one the source wore is not the one the destination does. Nothing is silently dropped: a field the destination cannot
represent, or a metadata key it cannot carry, refuses the write and names it. A copy never
deletes work either, so a destination item the source no longer holds is left exactly as it
is and reported as `orphaned`.
<!-- llmlint: ignore-end[contracts_have_one_source_or_a_drift_gate] -->
**A copy either completes or leaves the destination as it found it.** A copy that cannot
finish — a field the destination refuses, a credential that expires, a rate limiter —
undoes what it has already written and takes back the items it created in that run, so the
retry starts from the destination you started from. That is what stops a half-written
project having to be re-run, and the re-run is the burst of writes that trips a hosted
destination's rate limiter. When the destination will not take one of them back, the
refusal says so and names what is still there rather than leaving you to find it.
`--json` gives one entry per item for a script to read:
```json
{"items": [{"source": "notes:ENG-142", "action": "updated", "destination": "work:ENG-142"}]}
```
`action` says which of the four things above happened to that item, and `destination` is
`null` only for a dry run that would have created something. The vocabulary itself is
published rather than restated here: it is the `CopyAction` root of `onetaskgraph schema`,
which is what both SDKs are generated from and what the journeys validate this output
against.
A copy that reaches a source which counts its own requests — `github-projects` does — also
says what it **spent**: the requests those sources sent for the command, and what that cost
each budget they draw on, with a flag on any amount that is partly a modelled lower bound
rather than a figure the backend reported. It is the source's own account, summed over the
command, and a copy whose sources count nothing carries no `spent` at all rather than a
zero. Its shape is the `spent` property of the `CopyReport` root of `onetaskgraph schema`.
### Exit codes
| Code | Meaning |
| --- | --- |
| `0` | Success — every source asked, every source answered. |
| `1` | The command failed while running: an id that names nothing, a configuration it will not run on, a source name nothing configures. |
| `2` | The invocation itself was wrong — an unknown flag, a value out of range. |
| `4` | The query ran and at least one source did not answer. The others' results still stand and the failure is named on standard error. A write — a copy, or `task status set` — also exits `4` when it landed and a task it delivers could not be kept in step; its `delivered` list says which. |
`--allow-partial` says a partial answer is acceptable and turns `4` into `0`. Nothing else
does: a run that lost a source never exits `0` unless you asked for that.
With machine output selected — `--json`, `--output json`, or `output: json` set in a
document, by `--set` or by `ONETASKGRAPH_OUTPUT` — a command that exits `1` also writes
exactly one document to standard output, and nothing else goes there. Its shape is
published rather than restated here: it is the `FailureDocument` root of `onetaskgraph
schema`, which describes every member and is what both SDKs are generated from and what
the journeys validate this output against.
Its `class` is the member to branch on: `refused` means asking again unchanged gets the
same answer, and `transient` — a rate limit, or a source that could not be reached — means
it may not. The standard error line and the exit code are the same with
or without it, and exit `2` writes no document. A partial answer at exit `4` carries the
same `class` on each entry of its `errors`.
### Paging
`--limit N` gives you a page and, when there is more, the token for the next one:
```bash
onetaskgraph task list --limit 20
# ... rows ...
# next page: --page 5b7b22736f7572...
```
Rows are interleaved across the selected sources — one from each in configured-name order,
then the next from each — and within a source they keep that source's own order. The turns
carry on across page boundaries, so a walk returns the same rows in the same order whatever
page size you choose: `--limit 3` and `--limit 50` differ in how many round trips they cost
and in nothing else. The token is the engine's own; a source's cursor travels inside it
untouched, and a walk returns every row exactly once.
A token belongs to the query that produced it. Resuming it from a query that asks for
something else — another `--label`, another `--search`, another `--source`, the other
`--direction` — is refused rather than answered, because every cursor inside it is a
position in the result set the original query returned, and picking up there under new
filters returns real rows from a walk you are not doing. Change the query, drop `--page`.
## Install
The command-line tool ships as a self-contained binary. Once a release is cut, install it
whichever way suits your machine:
```bash
cargo install onetaskgraph # from crates.io
uv tool install onetaskgraph-cli # from PyPI, no Rust toolchain needed
npm install -g onetaskgraph-cli # from npm, no Rust toolchain needed
```
For Rust, the SDK surface is the engine crate itself rather than a separate wrapper
package. Add it when the application should link the engine, or add either subprocess SDK
when it should drive the installed binary:
```bash
cargo add onetaskgraph-core onetaskgraph-plugin-api serde_json
cargo add tokio --features macros,rt-multi-thread
uv add onetaskgraph-sdk # Python
bun add @onetaskgraph/sdk # TypeScript
```
The engine links its local sources — `in-memory`, `local-md` and `subprocess` — in every
build. The two that reach a network are features no default enables, so an application that
wants only a local store does not compile an HTTP and TLS stack it never runs: add
`--features github-projects,linear` (or either one) to the first line for GitHub Projects or
Linear. A configuration naming one a build left out is refused with the feature that
enables it.
This complete example constructs an engine over two in-memory sources, copies a task through
`Engine::copy`, inspects the outcome, and reads the destination back through the engine:
```rust
use onetaskgraph_core::{
Config, CopyItems, CopyRequest, CopyScope, Engine, Environment, GlobalId, Secrets,
};
use onetaskgraph_plugin_api::SourceName;
use serde_json::json;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let config = Config::from_document(json!({
"sources": {
"drafts": {
"plugin": "in-memory",
"config": {"tasks": [{
"id": "T-1",
"title": "Ship the guide",
"content": "Publish the Markdown workflow.",
"status": {"category": "todo", "name": "Todo"},
"labels": [],
"metadata": {},
"repositories": []
}]}
},
"work": {"plugin": "in-memory", "config": {}}
}
}))?;
let secrets = Secrets::load(Environment::default())?;
let engine = Engine::build(&config, &secrets);
let report = engine.copy(&CopyRequest {
items: CopyItems::new(vec!["drafts:T-1".parse::<GlobalId>()?])
.expect("a copy names at least one item"),
scope: CopyScope::Tasks,
destination: SourceName::new("work")?,
match_by: None,
recreate: false,
dry_run: false,
}).await?;
let outcome = &report.items[0];
assert_eq!(outcome.source.to_string(), "drafts:T-1");
assert_eq!(outcome.destination().unwrap().to_string(), "work:T-1");
assert_eq!(outcome.action.name(), "created");
println!("{} -> {} ({})", outcome.source,
outcome.destination().expect("the copy created a destination"),
outcome.action.name());
let copied = engine.task(outcome.destination().unwrap()).await?;
assert_eq!(copied.items[0].item.title, "Ship the guide");
println!("{}", copied.items[0].item.title);
Ok(())
}
```
Unlike the Python and TypeScript SDKs, which spawn the compiled binary, a Rust consumer
links `onetaskgraph-core` and calls `Engine` in process. The engine and its copy semantics
remain the single implementation in either case.
To work on the repository instead, clone it and run `just bootstrap`; `just --list` shows
the rest.
## Configure
One YAML document, `onetaskgraph.yaml`, discovered upward from the working directory and
layered over a user-level file at `$XDG_CONFIG_HOME/onetaskgraph/config.yaml`:
```yaml
default_sources: [work, notes] # omitted means every configured source
page_size: 50
output: text # text | json
sources:
work:
plugin: linear
config: { api_key_env: LINEAR_API_KEY, team: ENG }
notes:
plugin: local-md
config: { root: ~/notes/tasks }
```
Every setting is reachable at three layers, lowest precedence first: **the file, then the
environment, then a command-line flag.**
An environment variable is `ONETASKGRAPH_` followed by the config path, each segment
upper-cased with `-` replaced by `_` and segments joined by a double underscore; a list is
comma-separated:
| Variable | Sets |
| --- | --- |
| `ONETASKGRAPH_PAGE_SIZE=100` | top-level `page_size` |
| `ONETASKGRAPH_DEFAULT_SOURCES=work,notes` | top-level `default_sources` |
| `ONETASKGRAPH_SOURCES__WORK__CONFIG__ROOT=/tmp/tasks` | the `root` of the source named `work` |
| `ONETASKGRAPH_SOURCES__GH_MAIN__PLUGIN=github-projects` | the plugin of the source named `gh-main` |
The mapping is unambiguous because a source name may not contain an underscore.
On the command line the same dotted path is `--set`, and a few common settings have named
flags of their own:
```bash
onetaskgraph config show --set sources.work.config.root=/tmp/tasks
onetaskgraph config show --page-size 100 --default-sources work,notes --json
```
`onetaskgraph config show` is what makes precedence something you can see rather than
something you have to reason about: it prints every setting, its value, and the layer it
came from — which file, which environment variable, or which flag — and `--json` renders
the same thing for a script.
That third column is the whole point: `default_sources` above came from an environment
variable, `page_size` from a flag that outranks the document's own value, and every
`sources.*` entry from the document, named by path.
### Relative paths in a configuration document
**A relative filesystem path a configuration document supplies is resolved against the
directory holding that document.** `onetaskgraph.yaml` is discovered by walking *upward*
from the working directory, so the document is very often not in the directory you ran the
command in — a `local-md` `root:` of `plans` in a checkout's own document means that
checkout's `plans`, whether you run from the checkout, from a crate three levels inside it,
or from a worktree beside it.
**A relative path the environment layer or a flag supplies keeps resolving against the
process working directory**, because there is no document to rebase it on:
`ONETASKGRAPH_SOURCES__PLANS__CONFIG__ROOT=plans` and `--set
sources.plans.config.root=plans` both mean `plans` under wherever the command is running.
Naming the directory outright is still how a launcher points a run at a store that is
neither beside its own document nor beside its working directory:
```bash
ONETASKGRAPH_SOURCES__PLANS__CONFIG__ROOT=/srv/plans onetaskgraph task list
```
`onetaskgraph config show` reports the resolved path beside the document that supplied it,
so what a run will really read is something you can see rather than something you have to
work out.
The rule reaches only the configuration fields a plugin itself declares as paths, and each
plugin's own page says which of its fields those are. It holds across the `subprocess` seam
too, so a `local-md` root relative to its document names the same directory in process and
behind the seam: the engine rewrites nothing in a `settings:` block, and the child learns
which document's directory to measure its declared fields from through the handshake.
[`docs/plugin-protocol.md`](./docs/plugin-protocol.md) §3.8 is the one statement of that
member, including when it is absent and what a plugin written before it does.
### Credentials
A configuration document never holds a credential — it names the environment variable that
does (`api_key_env: LINEAR_API_KEY`). Before resolving sources the CLI reads
`$XDG_CONFIG_HOME/onetaskgraph/secrets.env` (override with `ONETASKGRAPH_SECRETS_FILE`) as
`KEY=VALUE` lines with `#` comments, and applies each value **only where the process
environment does not already define that name** — so anything you exported wins. A missing
file is not an error. A credential is never printed, never in debug output, and never in a
log line.
There is exactly one name per credential everywhere — in that file, in the configuration,
in the documentation and in CI: `LINEAR_API_KEY` and `GH_PROJECTS_TOKEN`. Nothing anywhere
translates between spellings.
## Addressing
Every item is qualified by the source it came from and rendered `<source>:<native>` —
`work:ENG-142`, `notes:2026-08-inbox`. Parsing splits on the **first** colon, so a native
id may contain colons freely.
## Custom metadata and repositories
A task and a project each carry a caller-defined `metadata` map and the `repositories`
they concern, and a dependency edge names both its ends by kind and qualified id — so an
edge may cross projects, cross the task and project levels, and cross sources.
[`docs/metadata.md`](./docs/metadata.md) says which keys are reserved and where each source
keeps them.
The far end of the second row is in another source. It is reported by qualified id and kind
and never followed: opening it is a command of your own.
## Writing a source in another language
A source that is not a Rust crate speaks a line-oriented JSON protocol over stdio:
[`docs/plugin-protocol.md`](./docs/plugin-protocol.md) specifies it completely — the
framing, the capability handshake, one method per trait method, and the error envelope.
Configure one with the `subprocess` plugin, which names the program to run and hands it
its own settings verbatim:
```yaml
sources:
notes:
plugin: subprocess
config:
command: /usr/local/bin/my-source
args: [--serve]
secrets: [LINEAR_API_KEY] # forwarded in the handshake; nothing else is
settings: { root: ~/notes } # this source's own `config:` block
```
A source behind that seam is a source like any other: it declares its own capabilities,
so a plan says `pushed down` for what it applies itself, and the engine compensates for
the rest exactly as it does in process.
`onetaskgraph-source` is the **reference implementation of that plugin side**, and the test
host this repository drives its own journeys against: it hosts any built-in plugin over the
same protocol, so every journey runs a second time over a real pipe to a real second
process, and so you can read a working peer beside the specification.
**It is not part of the command-line interface.** Nothing `onetaskgraph` does needs it at
run time, and nothing may depend on finding it beside an installed CLI or resolve it off a
search path — a downstream test chain that did picked up an unrelated stale build and
treated a reference host as a runtime dependency. Read it, or build it, from a checkout:
```bash
cargo build -p onetaskgraph --bin onetaskgraph-source
```
## Licence
MIT. See [`LICENSE`](./LICENSE).