Why

Slack sends are currently text/media-only through the action path. To leverage Block Kit broadly, we need first-class blocks support in sendMessage.

Dependency

• Depends on Slack: improve Block Kit interaction handling (foundation) #18180, feat(slack): capture Block Kit view_closed lifecycle events #18234, feat(slack): use static_select for large slash arg menus #18242, and feat(slack): route modal interactions with private metadata #18252.
• If reviewing before dependencies merge, review tip commit: 469e7dc36.

What This PR Adds

• In /Users/solvely/Projects/OpenClaw/src/agents/tools/slack-actions.ts:

  • sendMessage now accepts optional blocks.
  • blocks can be provided as:
    • JSON string
    • array object
  • validation ensures at least one of content, blocks, or mediaUrl is present.

• In /Users/solvely/Projects/OpenClaw/src/slack/actions.ts:

  • forwards optional blocks to Slack sender.

• In /Users/solvely/Projects/OpenClaw/src/slack/send.ts:

  • supports posting Block Kit blocks via chat.postMessage.
  • sends a single block message with fallback text when blocks are present.
  • guards unsupported combination: blocks + mediaUrl.

Behavior

• Existing text/media send behavior remains unchanged.
• New path allows robust Block Kit sends through the Slack action tool.
• Invalid blocks JSON returns a clear error.

Validation

• pnpm check
• pnpm exec vitest run --config vitest.e2e.config.ts src/agents/tools/slack-actions.e2e.test.ts

Reviewer Focus

• src/agents/tools/slack-actions.ts
• src/slack/actions.ts
• src/slack/send.ts
• src/agents/tools/slack-actions.e2e.test.ts