bug: text content blocks must be non-empty in custom provider

[JackFGreen]

Description

I use Figma mcp and skill to create React component, chat is ok in TUI, but when it downloads img from figma, there is a error stop tasks.

skill: https://skills.sh/figma/mcp-server-guide/implement-design
mcp: https://github.com/figma/mcp-server-guide

  "mcp": {
    "figma": {
      "type": "remote",
      "url": "https://mcp.figma.com/mcp",
      "enabled": true,
    },
  },

provider config

    "xxx": {
      "name": "xxx",
      "npm": "@ai-sdk/openai-compatible",
      "models": {
        "claude-sonnet-4-5-20250929": {
          "name": "claude sonnet 4.5",
        },
      },
      "options": {
        "baseURL": "xxx",
        "apiKey": "xxx",
      },
    },

error

InvokeModelWithResponseStream: operation error Bedrock Runtime: InvokeModelWithResponseStream, 

https response error StatusCode: 400, RequestID: e0741fc6-7c69-4ac5-bbe5-941f009e79fc, 

ValidationException: messages: text content blocks must be non-empty

logs

ERROR 2026-03-06T06:44:14 +1ms service=llm providerID=xxx modelID=claude-sonnet-4-5-20250929 sessionID=ses_33e1c3fe3ffeRM9DMKE2gFIm45 small=false agent=build mode=primary error={"error":{}} stream error
ERROR 2026-03-06T06:44:14 +1ms service=session.processor error="/chat/completions" cannot be parsed as a URL. stack="TypeError: \"/chat/completions\" cannot be parsed as a URL.\n    at URL (unknown)\n    at url (../../node_modules/.bun/@ai-sdk+openai-compatible@1.0.32+d6123d32214422cb/node_modules/@ai-sdk/openai-compatible/dist/index.mjs:1428:23)\n    at doStream (../../node_modules/.bun/@ai-sdk+openai-compatible@1.0.32+d6123d32214422cb/node_modules/@ai-sdk/openai-compatible/dist/index.mjs:468:24)\n    at processTicksAndRejections (native:7:39)" process
INFO  2026-03-06T06:44:14 +1ms service=bus type=session.error publishing
INFO  2026-03-06T06:44:14 +0ms service=bus type=session.status publishing
INFO  2026-03-06T06:44:14 +0ms service=bus type=session.idle publishing
INFO  2026-03-06T06:44:14 +0ms service=bus type=message.updated publishing
INFO  2026-03-06T06:44:14 +1ms service=session.compaction pruning
INFO  2026-03-06T06:44:14 +0ms service=session.prompt sessionID=ses_33e1c3fe3ffeRM9DMKE2gFIm45 cancel
INFO  2026-03-06T06:44:14 +0ms service=bus type=session.status publishing
INFO  2026-03-06T06:44:14 +0ms service=bus type=session.idle publishing
INFO  2026-03-06T06:44:14 +1ms service=session.compaction pruned=0 total=0 found
INFO  2026-03-06T06:44:16 +1292ms service=bus type=session.updated publishing
INFO  2026-03-06T06:44:58 +42099ms service=default worker shutting down
INFO  2026-03-06T06:44:58 +1ms service=default disposing all instances
INFO  2026-03-06T06:44:58 +0ms service=bus type=* unsubscribing

Plugins

No response

OpenCode version

1.2.20

Steps to reproduce

1. copy figma link

2. in tui make a component <figma_link>

Screenshot and/or share link

Operating System

macOS 15.1

Terminal

Ghostty

[github-actions]

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

• ValidationException: text content blocks must be non-empty when using Bedrock Runtime #15715: Same error ValidationException: messages: text content blocks must be non-empty with Bedrock Runtime / custom provider — the root cause appears identical.

If your issue is distinct (e.g. it only occurs specifically when an MCP tool returns image content from Figma), please add that clarification so this can be tracked separately.