[FEATURE] Add skill/tool frontmatter flag to auto-expand bash output in tool tip

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently, large bash output in tool tips is collapsed by default (… +N lines (ctrl+o to expand)). This is fine for most tool calls, but for skills that are designed to display output (e.g. a todos list, a status summary), the collapsed format requires an extra keypress and the output isn't immediately readable.

Current workaround: Instruct Claude to write the output to response text — but this is slow (~3 sec per item for large outputs) since it streams token by token, whereas the tool tip captures it instantly.

Expected behavior: expand-output: true in a skill's frontmatter causes the bash tool result to render expanded without requiring ctrl+o, and without Claude re-echoing the content in response text.

Use case: /todos skill — output is available instantly in the collapsed block, but requires a manual expand. Auto-expansion would make this equivalent to running the command directly in a terminal.

• Churned for 46y

Proposed Solution

Request: Add a frontmatter flag (e.g. expand-output: true) to skill SKILL.md files that tells the Claude Code UI to auto-expand the bash tool tip for that skill invocation.

Alternative Solutions

Current workaround: Instruct Claude to write the output to response text — but this is slow (~3 sec per item for large outputs) since it streams token by token, whereas the tool tip captures it instantly. Writing 30 todos can take 45s.

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

I use my /todos skill (or bash call). It calls my database. Database returns 30 todos in 138ms, Claude proceeds to SLOWLY write the response in a collapsed tool output then SLOWLY write 30 todos over the next minute. SAME DATA, SAME FORMAT, but he seems to be using a chisel and stone instead of copy and paste.

Additional Context

_No response_