> ## Documentation Index
> Fetch the complete documentation index at: https://docs.medera.info/llms.txt
> Use this file to discover all available pages before exploring further.
# Canvas Node Types
> 16 core node types + 8 BH-OS rail node types.
The canvas ships **16 core node types** and **8 BH-OS rail** node types. Each runner extends and is registered with the.
## Core nodes (3)
| Type | Runner | Purpose |
| :------ | :-------------- | :---------------------------------------------------------- |
| `start` | `Start runtime` | Workflow entry. Defines input variables. |
| `end` | `End runtime` | Workflow exit. Marks execution complete with output values. |
| `note` | annotation only | Documentation node — no runtime effect. |
## Logic & control (5)
| Type | Runner | Outputs |
| :-------------- | :------------------ | :---------------------------------------------------------------------------- |
| `condition` | `Condition runtime` | `true` / `false` (field + operator + value) |
| `transform` | `Transform runtime` | `default` (Handlebars / Liquid template) |
| `classify` | `Classify runtime` | Dynamic — one per declared category |
| `wait` | `Wait runtime` | `default` (after delay or cron) |
| `user-approval` | `Approval runtime` | `approved` / `rejected` — pauses execution and writes to `workflow_approvals` |
## Healthcare agents (4)
| Type | Runner | Outputs |
| :-------------- | :---------------- | :--------------------------------- |
| `intake-agent` | `Intake runtime` | `success` / `escalate` / `error` |
| `scribe-agent` | `Scribe runtime` | `success` / `error` |
| `therapy-agent` | `Therapy runtime` | `success` / `concern` / `error` |
| `triage-agent` | `Triage runtime` | `urgent` / `routine` / `self_care` |
## Integration & data (4)
| Type | Runner | Outputs |
| :----------- | :------------------- | :------------------------------ |
| `guardrails` | | `pass` / `fail` |
| `ehr-sync` | `EHR sync runtime` | `success` / `error` |
| `fhir-query` | `FHIR query runtime` | `success` / `error` |
| `escalate` | `Escalation runtime` | (terminal — sends notification) |
## BH-OS rails (8)
The BH-OS rails are typed runners backed by. Each rail wires the workflow into a corresponding backend service.
Clinical assessment runner
Triage routing
Referral generator + closed-loop
Prior authorization workflow
Measurement-Based Care
HEDIS / MIPS capture
Provider network logic
e-Rx network e-Rx + DDI
## Sample composition
## Validation
`Node runtime.validate(node)` enforces required fields per node type at design time. Connections are type-checked — a `condition` node's `true` port can only connect to a node that accepts the condition's state output shape.
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## What's next
Template resolution and template syntax.
Snapshots, sandbox-first deploys, WORM audit.
HIPAA + 42 CFR Part 2 rules.
Template-driven data shaping.