Query Session Graph

Traverse a graph session object using a structured query AST.

POST `/revisions/:id/data/query` (Command: `query_session_graph`)

Request Body

Parameter	Type	Required	Description
`engine`	string	Yes	Must be `workflow_blobhub`.
`command`	string	Yes	Must be `query_session_graph`.
`session_id`	string	Yes	The ID of the session that owns the graph envelope.
`alias`	string	Yes	Alias of the graph session object.
`query`	object	Yes	Traversal query AST. See structure below.

Query AST

The query object has two fields:

Field	Type	Required	Description
`start`	array	Yes	Selects the initial working set.
`steps`	array of arrays	No	Ordered traversal steps. Defaults to `[]`.

start — a list of one or two elements: ["V"], ["E"], ["V", "<id>"], or ["E", "<id>"].

"V" — start from all vertices in the graph (no id) or a single vertex by id.
"E" — start from all edges in the graph (no id) or a single edge by id.

steps — each step is a non-empty list where the first element is the step name and the remaining elements are its arguments:

Step name	Arguments	Description
`out`	`type?` (string)	Follow outgoing edges; optionally filter by edge label.
`in`	`type?` (string)	Follow incoming edges; optionally filter by edge label.
`both`	`type?` (string)	Follow edges in both directions; optionally filter by edge label.
`outE`	`type?` (string)	Move to outgoing edge elements (instead of neighbor vertices).
`inE`	`type?` (string)	Move to incoming edge elements.
`bothE`	`type?` (string)	Move to edge elements in both directions.
`inV`	—	From edge elements, resolve the `to_id` vertex.
`outV`	—	From edge elements, resolve the `from_id` vertex.
`hasLabel`	`label` (string)	Retain elements whose `labels` array contains the given label.
`has`	`key`, `op`, `value`	Retain elements where `props[key] <op> value`. `op` is one of `eq`, `neq`, `lt`, `lte`, `gt`, `gte`.
`values`	`key` (string)	Extract `props[key]` for each element (terminal — result becomes a list of scalars).
`properties`	—	Extract the full `props` object for each element (terminal).
`project`	`keys` (string[])	Extract a subset of `props` keys for each element (terminal).
`path`	—	Return the traversal path (list of element_ids) for each walker (terminal).
`limit`	`n` (integer)	Keep at most `n` elements from the current working set.
`dedup`	—	Remove duplicate elements (by `element_id`) from the working set.
`count`	—	Return the count of elements in the working set (terminal — result is an integer).

Terminal steps (values, properties, project, path, count) convert the working set to a non-element result. Only limit, dedup, and count are valid after a terminal step.

Hard Caps

The server enforces four hard caps on every query regardless of the AST:

Cap	Description
`max_depth`	Maximum number of steps allowed in a single query.
`max_fanout`	Maximum elements expanded by a single adjacency hop.
`max_results`	Maximum size of the working set / final result.
`max_elements`	Maximum cumulative element fetches across all steps.

Exceeding any cap returns graph_traversal_limit_exceeded.

Response

Parameter	Type	Description
`result`	array of object, array, or integer	Traversal result. A list of elements (default), a list of scalars/dicts (after `values`/`properties`/`project`/`path`), or an integer (after `count`).

Errors

invalid_graph_envelope — the alias does not exist or its value.type is not "graph".
invalid_graph_query — the query AST is malformed or contains unsupported step types.
graph_traversal_limit_exceeded — the query hit a server-side traversal cap.

Example

{
  "engine": "workflow_blobhub",
  "command": "query_session_graph",
  "session_id": "sess_001",
  "alias": "task_graph",
  "query": {
    "start": ["V"],
    "steps": [
      ["hasLabel", "task"],
      ["has", "status", "eq", "open"],
      ["out", "depends_on"],
      ["limit", 10]
    ]
  }
}

{
  "result": [
    {
      "element_id": "task:1",
      "type": "vertex",
      "labels": ["task"],
      "props": { "title": "Research", "status": "in_progress" },
      "rev": 2,
      "created_at": "2026-06-06T10:00:00.000000+00:00",
      "updated_at": "2026-06-06T10:00:01.000000+00:00",
      "user_id": "usr_001"
    }
  ]
}

Overview

Workflow

Scheduler

ONNX

Query Session Graph

POST `/revisions/:id/data/query` (Command: `query_session_graph`)

Request Body

Query AST

Hard Caps

Response

Errors

Example

See also

​POST /revisions/:id/data/query (Command: query_session_graph)

​Request Body

​Query AST

​Hard Caps

​Response

​Errors

​Example

​See also

POST `/revisions/:id/data/query` (Command: `query_session_graph`)

Request Body

Query AST

Hard Caps

Response

Errors

Example

See also