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Workflow Nodes

A Tryll workflow is a graph of nodes, each responsible for one step of the per-turn loop. Fourteen node types ship in the box; together they cover the common patterns of conversational inference (generation, retrieval, intent classification, instructions, detection, fallback, guardrails, composition, routing).

Every producing node below writes its text output into a named slot on the turn's shared blackboard, consumed by downstream nodes via input or by any template's {{slot.<name>}} tag — see Slots and inter-node value passing.

Nodes are referenced by their NodeType name on the wire protocol:

Node NodeType Exit routes Use for
Generate Generate default Language-model inference. The workhorse.
Generate and Speak GenerateAndSpeak default Fused LLM generation + streaming TTS.
Speak Speak default TTS-only; voices its input-resolved slot (default: user_message, like every other input-bearing node).
Transform Transform default Model-free: renders a Mustache template into its own slot. No inference, no wire emission — composition/rewriting glue between other nodes.
Instruction Instruction default Attach a named instruction slot to the current interaction; rendered by downstream Generate via {{#instructions}} / {{slot.<name>}}.
Retrieve Retrieve found, not_found Vector search over an embedded string storage — the R in RAG.
Classify Intent ClassifyIntent found, not_found Top-1 embedding similarity against a labelled KB; attaches an IntentionComponent for downstream routing.
Classify Intent (LLM) ClassifyIntentLLM found, not_found Intent classification via the language model's first-token logprobs.
Intent to Instruction IntentToInstruction default Look up the detected intent in a Map string storage and write the matching instruction slot.
Tool Call ToolCall tool_called, no_tool_called Detect whether the model wants to call an external tool.
Canned Response CannedResponse default Emit a fixed reply from a string storage without calling the model.
Regex Guardrail RegexGuardrail triggered, not_triggered Regex-match an input slot (default user_message); branch the graph on pattern hits.
Pause Pause default No-op checkpoint; the executor suspends the turn after this node until the client sends ResumeAgentRequest.
Branch Branch then, else Model-free conditional routing on a turn-local slot or an agent variable — the only node that can read what another node produced this turn.

Exit-route legend

Every node's reference page lists its named exits. Each exit is a typed string field on the node's params object (e.g. default_exit, triggered_exit). An empty string routes the turn to END (the default); a non-empty string must name another node in the graph. The server rejects graphs where an exit field names a missing node with error 3008 InvalidExitTarget.

Common patterns:

  • Straight line. Generate → default → END. Minimal single-turn agent.
  • Branch on guardrail. Guardrail → triggered → CannedResponse → END; Guardrail → not_triggered → Generate → default → END.
  • Instruction then generate. Instruction → default → Generate. The instruction's text is exposed as {{slot.<name>}} and {{#instructions}} in the Generate node's Mustache template.
  • Rewrite then retrieve. Transform → default → Retrieve (input set to the Transform node's name) → Generate. See Query rewriting for RAG.
  • Retrieve then generate. Retrieve → found → Generate; Retrieve → not_found → Generate (same target). The not_found path is fine — the projection drops to the user message alone.
  • Tool-call detection. ToolCall → tool_called → END (client handles the tool); ToolCall → no_tool_called → Generate.
  • Intent classification. ClassifyIntent → found → IntentToInstruction → default → Generate; ClassifyIntent → not_found → Generate (general answer, no instruction override). See How to build an intent-driven NPC.
  • Refusal fallback. Generate (hidden classification pass, send=None) → default → Branch (Contains/Equals on the verdict slot) → then → CannedResponse → END; Branch → else → Generate (the real answer) → default → END. Catches a model's own "I can't help with that" or an unsafe verdict without shipping the refusal text verbatim.

Params

Every node carries a list of (key, value) string pairs (NodeParam). Each node's reference page lists the keys it accepts. Unknown keys are currently silent; standardising on strict validation is planned.

Diagnostics

When the agent is created with enable_diagnostics = true, every node contributes to TurnComplete.debug_info. See agent parameters — diagnostics.