Transform Node¶

NodeType = Transform (wire ordinal 13)

A model-free input-composition node. It renders its Mustache template against the current turn's slots — user_message, any slot.<name> written earlier this turn, knowledge_<source>, and the #instructions iterable block — and writes the result into its own slot. It runs no inference and never emits anything on the wire: send = None, history_role = none, fixed.

Use it to compose or rewrite text before a downstream node consumes it via input — the flagship case is query rewriting: Transform rewrites the raw user message (fixing grammar, resolving "this"/"that" references against prior turns) into a self-contained query, which a following Retrieve or Generate node then reads via input = <transform node name>.

See Slots and inter-node value passing for the full mental model, and How-to: query rewriting for RAG for the end-to-end recipe.

Parameters¶

Param	Type	Default	Range	Structural	Description
`template`	Optional[str] (multiline)	inherit model default	—	—	Mustache template rendered at execution time against the user_message tag, slot. tags, knowledge_ tags, and the #instructions iterable block.
`output_name`	Optional[str]	inherit model default	—	✓	Name this node's output slot is stored under. Empty = the node's own name. Structural: immutable after creation — renaming would re-wire the slot dataflow that is validated once at agent creation.

Exits¶

Each exit is a structural string field on the node's params; its value names the target node (empty = END).

Exit	Param field	Description
`default`	`default_exit`	Default exit target after rendering. Empty string = END.

Exit routes¶

Exit	Condition
`default`	Taken after the template is rendered into the node's slot.

Diagnostics¶

When enable_diagnostics = true, this node contributes to debug_info.nodes[].diagnostics. See Turn Diagnostics JSON for the envelope.

Transform runs no model, so it emits a parameters section only.

Key	Meaning	Absent when
`parameters.template`	The Mustache template, in full — not truncated the way Generate's knowledge template is.	—
`parameters.output_name`	The configured output slot name.	Defaulting to the node name.

The node records the template but not the rendered result. To see what it produced, read that slot from the turn's interaction snapshot, or from the input.prompt[] of the node that consumed it.

Example¶

PythonC++

from tryll_client.graph import GraphDescription, TransformParams, RetrieveParams, GenerateParams

graph = (
    GraphDescription()
    .add_node("rewrite", TransformParams(
        template="Rewrite the user's message as a standalone question, "
                 "resolving pronouns against earlier turns: {{user_message}}",
        default_exit="retrieve",
    ))
    .add_node("retrieve", RetrieveParams(
        input="rewrite",
        embedded_string_storage="aquarium_kb",
        found_exit="generate",
        not_found_exit="generate",
    ))
    .add_node("generate", GenerateParams(input="rewrite", default_exit=""))
    .set_start_node("rewrite")
)

using namespace Tryll::Client;
using namespace Tryll::NodeParams;

TransformParamsT tp;
tp.template_ = "Rewrite the user's message as a standalone question: {{user_message}}";
tp.default_exit = "retrieve";

GraphDescription graph;
graph.AddTransform("rewrite", std::move(tp))
     .SetStartNode("rewrite");