Canva MCP: Tool registration fails with schema validation error "enum[0]: cannot be empty" despite successful authentication #33316

This issue might be a duplicate of existing issues. Please check:

• Error resolving schema reference '$ref' in Canva MCP tool when using custom API provider #29220: Error resolving schema reference in Canva MCP tool — same Canva MCP server and the same perform-editing-operations tool schema causing incompatibility with OpenCode's schema handling
• Google provider: schema validation error - numeric values in enum fields #33041: Google provider schema validation error with enum fields — same error pattern (function_declarations[N]...enum[0]) when using Google/Gemini models with MCP tool schemas
• Error GEMA 4 [Google AI Studio] * GeneratedContentRequest #32805: GenerateContentRequest tool schema error with Google provider — same error class affecting Google AI Studio with MCP tool definitions

This issue might be a duplicate of existing issues. Please check:

• Error resolving schema reference '$ref' in Canva MCP tool when using custom API provider #29220: Error resolving schema reference in Canva MCP tool — same Canva MCP server and the same perform-editing-operations tool schema causing incompatibility with OpenCode's schema handling
• Google provider: schema validation error - numeric values in enum fields #33041: Google provider schema validation error with enum fields — same error pattern (function_declarations[N]...enum[0]) when using Google/Gemini models with MCP tool schemas
• Error GEMA 4 [Google AI Studio] * GeneratedContentRequest #32805: GenerateContentRequest tool schema error with Google provider — same error class affecting Google AI Studio with MCP tool definitions

The GitHub bot suggested #29220 and #33041 as possible duplicates.

My issue appears closest to #29220 because it involves:

• Canva MCP (https://mcp.canva.com/mcp)
• Successful authentication
• Failure while registering Canva tool schemas

The failing path is:

function_declarations[25]
.parameters.properties[operations]
.items.any_of[8]
.properties[formatting]
.properties[link]
.any_of[0]
.enum[0]

I'm also seeing the issue across multiple models/providers after upgrading to OpenCode 1.17.9.

I upgraded to OpenCode 1.17.9 and can still reproduce.

Canva MCP is connected and authenticated.

The error path points to:
function_declarations[25]
.parameters.properties[operations]
.items.any_of[8]
.properties[formatting]
.properties[link]

This appears related to the perform-editing-operations Canva tool mentioned in #29220.

To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.

Reopening — this got auto-closed for staleness, not because it was fixed.

The failing path here (operations.items.any_of[8].properties[formatting].properties[link].any_of[0].enum[0]) is the same bug class as #46676: Gemini rejects a "" enum member wherever it appears in a tool schema, including nested inside anyOf. It looked Canva/$ref-specific because of where it showed up in the schema tree, but the actual fix is in opencode's Gemini tool-schema sanitizer, not the Canva server. #46676 strips empty-string enum members there and should fix this too.

Linking as the tracking issue for that PR.