slot-extractor

Overview

component-slot-extractor parses structured values out of a user’s natural-language utterance using regex-based rules per slot type. Its output flows directly into the prefill field of an Adaptive Card so a flow author can route a chat message and have the answering form open with fields already populated.

Core concept: the lawyer types

NDA between Acme Corp and us by 2026-07-15

→ the extractor returns {counterparty: "Acme Corp", due_date: "2026-07-15"} → the NDA intake card opens with both fields prefilled.

Key principles:

• Deterministic — regex per slot type; no LLM in v1, no probabilistic ranking
• Fail-safe — invalid user regex returns no match instead of panicking; unmatched required slots land in missing
• Capability-free — pure compute; no secrets, network, or LLM capabilities
• One-shot — single-utterance extraction; multi-turn slot filling is out of scope

The canonical M2 chain

inbound utterance
    │
    ▼
Fast2Flow → Dispatch{ target, utterance }
    │
    ▼
component-slot-extractor (utterance + flow.slot_schema)
    │
    ▼
component-adaptive-card (prefill = extractor.values)
    │
    ▼
form opens with fields already filled

A flow author declares the slots once at the flow level via the new slot_schema field. The slot-extractor node consumes that schema plus the dispatched utterance. The adaptive-card render node binds its prefill field to extractor.values — the flat name→value map ready for direct consumption.

Slot types

Type	What it matches
string	Requires a user-supplied pattern; emits the first capture group else the full match.
enum	Case-insensitive whole-word match against enum_values. First hit wins.
number	Default regex -?\d+(?:\.\d+)? unless pattern overrides. Emitted as a JSON number.
date	Pattern capture else default scan \d{1,4}[-/]\d{1,2}[-/]\d{1,4}; tries ISO 8601 → m/d/Y → d/m/Y; normalised to ISO 8601 on output.
boolean	Whole-word match against an i18n affirmative / negative token table (EN / ES / FR / DE / RU / PT / IT / NL).

A default_value on any slot fills the slot when no match was found (source: "default", confidence: 0.5).

SlotDefinition wire shape

{
  "name": "counterparty",
  "slot_type": "string",
  "pattern": "between\\s+([A-Z][\\w&. ]*?)\\s+and",
  "required": true,
  "enum_values": null,
  "default_value": null
}

enum_values is only meaningful for slot_type: enum. pattern is required for string, optional for number / date, ignored for enum / boolean.

Output shape

{
  "slots": [
    { "name": "counterparty",
      "value": "Acme Corp",
      "confidence": 1.0,
      "source": "regex" }
  ],
  "values": {
    "counterparty": "Acme Corp"
  },
  "filled":  ["counterparty"],
  "missing": ["due_date"],
  "all_required_filled": false
}

• slots — full ExtractedSlot records with confidence and source metadata. Use for inspection, debugging, and audit trails.
• values — flat name → primitive value map; mirrors slots[].value for filled slots only. Shape matches the adaptive-card prefill contract directly — bind this field, not slots.
• filled preserves the order of the input slot_definitions.
• missing contains only required slots that neither matched nor had a default_value.
• all_required_filled = missing.is_empty().

Declaring slots on a flow

Put the definitions at the top of the .ygtc flow under the M2.4a slot_schema field:

id: nda_intake
type: messaging
schema_version: 2

slot_schema:
  - name: counterparty
    slot_type: string
    pattern: 'between\s+([A-Z][\w&. ]*?)\s+and'
    required: true
  - name: due_date
    slot_type: date
    required: true

nodes: { ... }

The flow-level field is the single source of truth — Fast2Flow scoping, design-time tooling, and the runner all read from it.

Note

At execute time the runner detects ai.greentic.component-slot-extractor nodes and injects the flow-level slot_schema into the invocation as slot_definitions, so the node payload only has to forward the utterance. An explicit node-level slot_definitions key still wins (back-compat with flows authored before injection landed). Requires greentic-runner ≥ 1.1.26775859893.

Binding into adaptive-card prefill

The extractor’s values map is already keyed by slot name with primitive values — exactly the shape the adaptive-card prefill field expects. In your flow’s adaptive-card node, bind each input id to the corresponding values entry:

nodes:
  render_card:
    component: component-adaptive-card
    inputs:
      template: nda_intake_card
      prefill:
        counterparty: "{{extract_slots.values.counterparty}}"
        due_date: "{{extract_slots.values.due_date}}"

Do not bind to extract_slots.slots — that is an array of ExtractedSlot records, not a flat map. The adaptive-card component will reject a non-object prefill value at render time.

Tip

slots vs values — when to use which. Use values for prefill and any downstream node that needs plain slot primitives. Use slots when you need the full ExtractedSlot record (confidence score, source tag) — for example in audit logging, conditional branching on confidence thresholds, or debugging extraction quality.

Prefill precedence

The adaptive-card component honours this precedence at render time:

prefill > payload > session > state > template_params

So prefill = extractor.values always wins over any default values the card template carries. Documented in detail on the Adaptive Cards page.

What’s deferred

• LLM fallback — v1 is regex-only; locked design.
• Natural-language dates — “today”, “next Tuesday”, “in 3 days” not supported; would need chrono-english.
• Multi-turn slot filling — single utterance, one-shot. A second utterance hits the extractor independently.
• Cross-utterance memory — out of scope for the extractor; lives in the flow’s session state if a flow needs it.

Worked example

See pack/legal-nda-demo in greentic-examples for the full NDA intake flow that exercises this chain end-to-end.