# canvas.updateHtml
mutation write
Use when the requested change exactly matches canvas.updateHtml; read the current state first when a version or identifier may have changed.
## Before calling
- Authenticate as the accountable Enhance person.
- Use only resource identifiers returned by an earlier capability result or supplied by the person.
- Reuse clientToken only when retrying this exact mutation input.
## Input
Show complete JSON Schema
```json
{"$schema":"https://json-schema.org/draft/2020-12/schema","type":"object","properties":{"canvasRef":{"type":"string","minLength":1,"description":"Canvas UUID or full canvas/selection URL. Preserve the supplied scope."},"waitMs":{"default":1500,"description":"Additional polling for native HTML compilation. Preparation alone never commits.","type":"integer","minimum":0,"maximum":5000},"snapshotToken":{"type":"string","minLength":1,"maxLength":16384},"html":{"type":"string","minLength":1},"removeNodeIds":{"default":[],"maxItems":1000,"type":"array","items":{"type":"string","minLength":1}}},"required":["canvasRef","snapshotToken","html"],"additionalProperties":false}
```
### Example
Show example input
```json
{
"canvasRef": "00000000-0000-4000-8000-000000000010",
"snapshotToken": "eyJwcm90b2NvbCI6ImVuaGFuY2UtY2FudmFzLWVkaXRhYmxlLzEiLCJjYW52YXNJZCI6IjAwMDAwMDAwLTAwMDAtNDAwMC04MDAwLTAwMDAwMDAwMDAxMCIsInZlcnNpb24iOjEsInJvb3ROb2RlSWQiOiJyb290Iiwic2NvcGVOb2RlSWRzIjpbXSwic2NvcGVQYWdlSWQiOm51bGwsImRpZ2VzdCI6ImJkNWM0OGMzYTM2Njc0ZDEyZWIxMjVhMWI0YWJkMzk0ZGIyNjRjZjNhMjhlNjJiZWRhODcxZjJmYTkyMjMzYTMifQ",
"html": "",
"removeNodeIds": []
}
```
## Result
Returns a typed canvas.updateHtml result from the Enhance API without transport-specific prose.
## Recovery
- BAD_REQUEST: correct the named fields and call again.
- UNAUTHORIZED: restore Enhance authentication, then retry once.
- FORBIDDEN or NOT_FOUND: check the supplied resource and selection; do not substitute unrelated content. Ask for corrected access or scope if needed.
- CONFLICT: read the current resource, merge the intended change, and retry with its version.
- INTERNAL: run Enhance diagnostics, report the failure, and stop repeating the call.
## Continue with
- Read the affected canvas resource to confirm the result.
Compatibility: `332e447334275d6842ff27db03a407429e5a6f22b7a3e003912ccd2e32098df7`.