Why

After adding Block Kit support for sendMessage, edits still required plain text. This slice brings editMessage to parity so existing Slack messages can be upgraded/updated with blocks.

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, feat(slack): route modal interactions with private metadata #18252, and feat(slack): support Block Kit blocks in sendMessage #18257.
• If reviewing before dependencies merge, review tip commit: ffe8c1e83.

What This PR Adds

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

  • editMessage accepts optional blocks (JSON string or array)
  • allows empty content when blocks provided
  • validates at least one of content or blocks

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

  • editSlackMessage forwards optional blocks to Slack chat.update
  • keeps text fallback safe (" ") when content is empty

• In /Users/solvely/Projects/OpenClaw/src/agents/tools/slack-actions.e2e.test.ts:

  • adds edit tests for JSON blocks, array blocks, and required-field validation

Behavior

• Existing text edits remain unchanged.
• New path supports block-based message updates without requiring text content.

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/agents/tools/slack-actions.e2e.test.ts