Helix Query Authoring

Write Helix Rust DSL queries in a way that is schema-aware, explicit, and easy for agents to reason about.

When To Use

Use this skill when the task is to:

• write a new Helix query in Rust
• revise an existing Helix Rust DSL route
• add a stored query for deployment
• choose between read_batch() and write_batch()
• add traversal, projection, pagination, BM25 search, or vector search to an existing query

Do not use this skill as the main guide for inline POST /v1/query payloads. Use the dynamic-query skill for that.

First Steps

Before writing any query code:

1. Inspect the local repo for existing labels, edge labels, properties, and route patterns.
2. Find the closest existing query and reuse its naming, projection, and scoping style.
3. Decide whether the route is a read or a write.
4. Identify the narrowest indexed anchor before planning the traversal.

If the local repo is thin on Helix examples, use the companion files in this skill:

1. EXAMPLES.md — working end-to-end Rust queries (reads, writes, search, repeat, branching, upsert, for_each_param).
2. REFERENCE.md — full builder catalog organized by category, with typestate notes.

Open REFERENCE.md whenever you need a builder beyond the common surface (add_e, drop_edge_by_id, create_vector_index_nodes, repeat, choose, coalesce, optional, aggregate_by, group_count, inject, order_by_multiple, expression case, etc.) — do not invent method names from memory.

Core Authoring Rules

1. Start With The Right Batch Type

Use:

• read_batch() for read-only routes
• write_batch() for any mutation

If the query adds nodes, adds edges, updates properties, or deletes graph data, it is a write route.

2. Anchor Narrow, Then Traverse

Prefer this anchor order:

1. node ID or edge ID
2. unique property lookup
3. equality-indexed property lookup
4. scoped label scan
5. broad label scan as a last resort

Do not start from a broad label scan when the application already has an indexed identifier like entityId, externalId, userId, tenantId, or a similar key.

3. Reuse Existing Property And Label Casing

Do not normalize names to your own preferred style.

If the application uses entityId, updatedAt, FOLLOWS, or RelatesTo, reuse those exact names.

4. Filter Early

Apply scope and status filters before broad traversal whenever possible.

Common examples:

• tenant filters like tenantId or userId
• soft-delete or archived filters such as empty or null deletedAt
• specific ID filters before both, out, or in_

5. Keep Output Shape Intentional

Use:

• project(...) for stable service-facing response shapes
• value_map(...) when returning all or many properties is acceptable
• edge_properties() for edge streams

Do not return oversized properties like embeddings unless the caller explicitly needs them.

6. Preserve Search Scope

For BM25 and vector search:

• keep the chosen text or vector property explicit
• preserve tenant scope when the index is scoped
• post-filter only when the search API cannot express the scope directly

7. Use Traversal Controls Deliberately

Apply dedup, limit, range, skip, count, and first because the route needs them, not by habit.

repeat(...) is often used with a deliberate bounded depth. Do not assume arbitrary runtime repeat depth unless the local code already supports it.

8. Prefer Explicit Write Branching Over Invented MERGE Semantics

When you need create-or-update behavior, follow this pattern:

1. load existing nodes
2. branch with var_as_if
3. update when found
4. create when missing

9. Know The Full Builder Surface

The DSL is larger than the canonical examples below suggest. Before reaching for a workaround, check REFERENCE.md — there is likely a direct builder.

Category	Primary builders	Notes
Sources	g().n(...), n_where, n_with_label, n_with_label_where, e, e_where, e_with_label, e_with_label_where, vector_search_nodes_with, text_search_nodes_with, vector_search_edges_with, text_search_edges_with	Anchor narrowly — indexed ID first, then label scope.
Traversal	out, in_, both, out_e, in_e, both_e, out_n, in_n, other_n	Edge-valued forms (*_e) switch the stream type.
Filters	has, has_label, has_key, where_, dedup, within, without, edge_has, edge_has_label	Predicate::* + Predicate::*_param for parameterized comparisons.
Limits	limit, skip, range	All accept usize or Expr.
Variables	as_ / store, select, inject	Cross-query refs via NodeRef::var, EdgeRef::var, NodeRef::param, EdgeRef::param.
Ordering	order_by, order_by_multiple	Use Order::Desc for descending.
Aggregation	count, exists, group, group_count, aggregate_by	AggregateFunction::{Count,Sum,Min,Max,Mean}.
Branching	union, choose, coalesce, optional	Each arm is a sub() sub-traversal.
Repeat	repeat(RepeatConfig::new(sub).times(n).until(pred).emit_all().max_depth(100))	Always bound with times or until; default max_depth is 100.
Projection	values, value_map, project, edge_properties	project mixes PropertyProjection (incl. renames) and ExprProjection.
Expressions	Expr::prop, Expr::val, Expr::id, Expr::timestamp, Expr::datetime, Expr::param, .add/.sub/.mul/.div/.modulo/.neg, Expr::case	Expr::Timestamp writes server UTC millis; Expr::DateTimeNow writes typed datetime.
Mutations	add_n, add_e, set_property, remove_property, drop, drop_edge, drop_edge_labeled, drop_edge_by_id	drop_edge_by_id is multigraph-safe.
Indexes	IndexSpec::node_equality / node_range / edge_equality / edge_range / node_vector / node_text / edge_vector / edge_text plus create_index / drop_index; convenience: create_vector_index_nodes, create_text_index_nodes, edge variants	Use .create_index(spec) from a write batch.
Transport	DynamicQueryRequest::{read,write}(batch).with_parameter_value(...).with_parameter_type(...).to_json_string()	Bridge from Rust DSL to the JSON payload (helix-query-json-dynamic).

See REFERENCE.md for signatures and typestate constraints.

Canonical Examples

Read By Indexed Identifier

read_batch()
    .var_as(
        "user",
        g().n_with_label("User")
            .where_(Predicate::eq_param("userId", "userId"))
            .project(vec![
                PropertyProjection::new("$id"),
                PropertyProjection::new("userId"),
                PropertyProjection::new("name"),
            ]),
    )
    .returning(["user"])

Explicit Create Or Update

write_batch()
    .var_as(
        "existing",
        g().n_with_label("User")
            .where_(Predicate::eq_param("userId", "userId")),
    )
    .var_as_if(
        "updated",
        BatchCondition::VarNotEmpty("existing".to_string()),
        g().n(NodeRef::var("existing"))
            .set_property("name", PropertyInput::param("name")),
    )
    .var_as_if(
        "created",
        BatchCondition::VarEmpty("existing".to_string()),
        g().add_n(
            "User",
            vec![
                ("userId", PropertyInput::param("userId")),
                ("name", PropertyInput::param("name")),
            ],
        ),
    )
    .returning(["updated", "created"])

Scoped Search Route

read_batch()
    .var_as(
        "results",
        g().vector_search_nodes_with(
            "Document",
            "embedding",
            PropertyInput::param("queryVector"),
            Expr::param("limit"),
            Some(PropertyInput::param("tenantId")),
        )
        .project(vec![
            PropertyProjection::new("$id"),
            PropertyProjection::new("title"),
            PropertyProjection::renamed("$distance", "distance"),
        ]),
    )
    .returning(["results"])

Anti-Patterns

Do not:

• invent labels, edge labels, or property names without checking the codebase
• start from broad scans when an indexed ID or scoped predicate exists
• return embeddings by default in search results
• ignore tenant scope on text or vector search
• add dedup or limit without a reason
• assume dynamic inline-query rules apply to stored Rust DSL routes
• treat BM25 as if it searches every property automatically

Validation Checklist

Before finishing:

• verify read_batch() versus write_batch() is correct
• verify labels, edge labels, and properties match the repo exactly
• verify the first anchor is the narrowest practical indexed set
• verify scope filters happen before or as early as possible
• verify the returned variable names and shape match service expectations
• verify text and vector routes preserve tenant scope when required
• verify large properties are omitted unless needed
• verify the query matches surrounding local style more than any generic example

Reference Files

• REFERENCE.md — full builder catalog (sources, traversal, predicates, expressions, projections, branching, repeat, mutations, indexes, dynamic-request transport).
• EXAMPLES.md — end-to-end Rust queries mirroring the scenarios in helix-query-json-dynamic/EXAMPLES.md, so you can move fluently between Rust DSL and JSON forms.