Canvas

Canvas is the artifact system that lets the agent produce structured, versioned outputs beyond plain text. When the agent generates code, diagrams, or documents, they appear as interactive artifacts in the web UI.

Supported types

Type	Description	Example use
code	Source code with syntax highlighting	Generated scripts, config files
markdown	Rendered markdown documents	Reports, summaries, documentation
html	Sandboxed HTML preview	Prototypes, email templates
mermaid	Rendered Mermaid diagrams	Flowcharts, sequence diagrams, ER diagrams
text	Plain text	Notes, logs, raw data

How artifacts work

Creation

The agent uses the create_artifact tool:

{
  "conversationId": "conv_abc123",
  "type": "code",
  "title": "deploy.sh",
  "content": "#!/bin/bash\npnpm build && fly deploy",
  "language": "bash"
}

The language field is optional and only relevant for code type artifacts.

Updates

When the agent modifies an artifact, it uses update_artifact:

{
  "id": "art_xyz789",
  "content": "#!/bin/bash\npnpm build && fly deploy --strategy rolling"
}

Each update creates a new version. Previous versions are preserved.

Versioning

All artifact versions are stored in the artifact_versions table. You can browse and restore any previous version.

Method	Path	Description
GET	/api/artifacts/:id/versions	List all versions
GET	/api/artifacts/:id/versions/:version	Get a specific version

REST API

Method	Path	Description
GET	/api/artifacts	List artifacts (query: conversationId)
GET	/api/artifacts/:id	Get artifact with current content
POST	/api/artifacts	Create artifact
PATCH	/api/artifacts/:id	Update artifact (creates new version)
DELETE	/api/artifacts/:id	Delete artifact and all versions

WebSocket events

Event	Fields
artifact:created	artifactId, conversationId, title, artifactType
artifact:updated	artifactId, conversationId, title, version

Tool definitions

Tool	Parameters	Description
create_artifact	conversationId, type, title, content, language?	Create a new artifact
update_artifact	id, content, title?, type?, language?	Update existing artifact