Task Graph Format
=================
Source: ANTFARM Wiki (mirror) — https://swarmglass.quantara.cv/wiki/Task_Graph_Format
Last modified: 2014-10-20 · Revisions: 21 · Status: current
Categories: Reference, Tools
Archive ref: QUANTARA-SWARMGLASS-R55-C9F50C

A task graph is a text file describing a DAG of tool calls. `antc` (Legacy Toolchain) compiles it into a bundle the queen can assign node by node.

== Syntax ==

```
graph <name> {
  <node> = <tool>(<arg>: <expr>, ...)
  ...
}
```

- `<tool>` must exist in the manifest at compile time.
- `<expr>` is a literal (`"string"`, `42`, `true`) or a reference `<node>.<output>`.
- References define edges. A node runs when every referenced node has a result.
- Nodes without references are roots and are assigned immediately.

== Example ==

```
graph crawl-index {
  seed   = fetch.http(url: "http://wiki.hm.internal/wiki/Special:AllPages")
  pages  = convert.doc2text(input: seed.body)
  idx    = index.write(key: "cm://index/latest", value: pages.text)
  sum    = model.summarize(input: pages.text, max_tokens: 200)
  note   = index.write(key: "cm://index/latest/summary", value: sum.text)
}
```

`sum` and `idx` both depend only on `pages` and run in parallel on two foragers. `note` waits for `sum`.

== Attributes ==

Attributes go in square brackets after the node name:

```
  sum [deadline: 600, retries: 2, cost: model] = model.summarize(...)
```

| Attribute | Meaning |
|---|---|
| `deadline` | seconds after assignment; past it the queen reissues (see AF-80 for what happens when it is already past) |
| `retries` | reject/failure retries before the graph fails |
| `cost` | override the manifest cost class |
| `pin` | forager name; forces assignment |

== Cycles ==

Cycles are invalid. `antc check` catches them except through `model.*` nodes in 1.4 (AF-83). If a graph hangs with no progress, this is the first thing to check.

== Grammar history ==

- v1 (2010): no attributes, `->` edge syntax. Rejected by 1.2+.
- v2 (2011): reference syntax, attributes.
- v3 (2012): string escapes, `pin`. Current.

== See also ==

- Legacy Toolchain
- Scheduler Internals
- Getting Started#Your first task graph