Canvas Sdk

Canvas SDK Reference

This skill provides comprehensive documentation for the Canvas Medical SDK, enabling development of Canvas plugins.

Grounding Rule — Read Before Answering

Never answer a Canvas SDK question from memory. Canvas's SDK surface (effects, events, data models, handlers, manifest fields, import paths) is Canvas-specific and changes often; the model's prior is frequently wrong or out of date. Confidently-wrong answers about Canvas APIs are worse than no answer.

Before stating any specific class name, import path, effect/event name, field name, method, or supported value:

1. Read coding_agent_context.txt from this skill's directory (see Usage below) and grep/search it for the relevant term.
2. Base your answer on what the bundled docs actually say.
3. Cite the source doc page URL (the ----- BEGIN PAGE https://docs.canvasmedical.com/... line that contains the content) so the user can verify it — the same way a high-quality grounded answer always links its source.

This applies to a one-line verbal question just as much as to code generation. If a question is even partially about an SDK capability and you have not yet consulted this skill in the current conversation, consult it first, then answer.

When to Use This Skill

Use this skill whenever a question, claim, or piece of code involves — even in passing — any of:

• Canvas SDK classes, methods, and APIs
• Event types and their context structures
• Effect types and their payloads (e.g. creating external events / ADT ingestion, banner alerts, tasks)
• Data models (Patient, Condition, Medication, etc.)
• Handler types (BaseHandler, SimpleAPI, Application, CronTask)
• Canvas CLI commands
• Plugin manifest structure
• Whether Canvas "supports" some capability, and how it is modeled

This includes short conversational questions, not just plugin-building work. Examples that REQUIRE consulting this skill before answering: "how do I ingest ADTs?", "what's the import path for the external event effect?", "what fields does X take?", "does Canvas have a built-in HL7 parser?". Do not answer any of these from memory.

Terminology / Aliases

Users describe Canvas surfaces with different names. Map them to SDK classes before deciding which handler to scaffold:

• "Note Application", "NoteApplication", "Charting app", "Charting application", "note tab", "tab inside a note" → an embedded application scoped to a note. Implement with NoteApplication (subclass of EmbeddedApplication, with SCOPE = ApplicationScope.NOTE preset). Located in canvas_sdk.handlers.application.
• "Embedded app", "embedded application" → EmbeddedApplication directly. Use this when the scope is something other than note, or when the user wants to set SCOPE explicitly.
• "Full chart app", "chart tab" → an Application registered with "scope": "full_chart" in CANVAS_MANIFEST.json (appears alongside the default "Chart" and "Profile" tabs).
• "App drawer application" → a plain Application launched from the app drawer.

When a user says "Charting app" or "NoteApplication", do not ask them to clarify — assume they mean a note-scoped embedded application (NoteApplication) unless they describe behavior that doesn't fit (e.g. "appears at the top of the chart" → full_chart scope).

Note Application templates: always auto-resize

Every HTML template rendered by a NoteApplication must wire up the Canvas RESIZE message pattern so the iframe grows to fit its content instead of showing its own scrollbar inside the note. Apply this by default — do not ask the user to confirm. Only omit it if the user explicitly says they want a fixed-height iframe with its own scroll.

The canonical pattern (full snippet in coding_agent_context.txt, under "Auto-resizing the Note Application iframe"):

• html, body { overflow: hidden; margin: 0; padding: 0; }
• Listen for INIT_CHANNEL → grab the MessagePort
• Post { type: 'RESIZE', height: document.body.offsetHeight } on connect and on every ResizeObserver tick

Custom chart summary sections: always ask about real-time

When building a custom patient chart summary section (PatientChartSummaryCustomSectionHandler), ask the user whether the section needs real-time updates before scaffolding. If yes, implement it with a WebSocketAPI + Broadcast from a BaseHandler listening for the relevant Canvas events.

The WebSocket channel name MUST include the patient id (e.g. chart-summary-{plugin_name}-{patient_id}). Never broadcast on a global channel — it leaks updates across patient charts and causes every connected client to re-render on every event. Full pattern + example in coding_agent_context.txt, under "Real-Time Updates for Custom Sections".

Key Documentation Sections

Handlers

• BaseHandler: Event-driven handlers responding to Canvas events
• SimpleAPI: HTTP endpoints and WebSocket handlers
• Application: UI applications launched from the app drawer
• EmbeddedApplication / NoteApplication: Embedded UI shown inside the chart or note (see Terminology above)
• CronTask: Scheduled task execution
• ActionButton: UI buttons in notes and patient headers

Events

• Record lifecycle events (patient, appointment, lab results)
• Command lifecycle events (prescribe, diagnose, assess, etc.)
• Search result events for customizing dropdowns

Effects

• AddBannerAlert: Display alerts in patient timeline
• AddTask: Create tasks for staff
• LaunchModalEffect: Open modals/panels
• Patient metadata effects
• Billing effects

Data Models

• Patient, Appointment, LabOrder, Medication
• Condition, AllergyIntolerance, Observation
• Note, Task, Staff, Team

Third-Party Libraries

• AWS S3
• LLM:
  • Anthropic Claude,
  • OpenAI ChatGPT,
  • Google Gemini
• Twilio
• SendGrid
• Extend.ai

Usage

IMPORTANT: The full SDK documentation is bundled with this skill. DO NOT download, curl, or fetch remote files.

The context file coding_agent_context.txt is located in the same directory as this SKILL.md file.

When you read this skill, note the path to this SKILL.md file, then read coding_agent_context.txt from that same directory.

For example, if this SKILL.md is at:

/some/path/skills/canvas-sdk/SKILL.md

Then read:

/some/path/skills/canvas-sdk/coding_agent_context.txt

To use this skill:

1. Read coding_agent_context.txt from this skill's directory - it already exists locally
2. Search the file for specific class names, event types, or effect types
3. Use the documentation to understand Canvas SDK capabilities
4. Cite the source doc page URL in your answer (the ----- BEGIN PAGE https://docs.canvasmedical.com/... URL whose section you used), so the answer is verifiable and grounded rather than asserted from memory

The context file contains ~20000 lines of comprehensive SDK documentation including all handlers, events, effects, and data models.

NEVER attempt to curl or download coding_agent_context.txt - it is already bundled here.