Thinking summaries deprecated in Claude Code v2.1.90+

[virtualian]

Date: 2026-04-14 · Affected: Claude Code ≥ v2.1.90

Problem

During long operations, the spinner showed only Thinking a bit longer… still working on it… instead of the live ∴ Thinking… narration that previous versions streamed. Extended thinking still ran (and was still billed), but the content was no longer visible.

Root cause

Claude Code v2.1.90 (April 1, 2026) changelog:

"Changed thinking summaries to no longer be generated by default in interactive sessions — set showThinkingSummaries: true in settings.json to restore"

The v2.1.107 entry "Show thinking hints sooner during long operations" only improves placeholder timing, not content visibility — upgrading further does not fix it.

Fix

One key in the user-level settings file, then restart Claude Code:

// ~/.claude/settings.json
{
  "showThinkingSummaries": true
}

Verification

• jq -e '.showThinkingSummaries' ~/.claude/settings.json → true + valid JSON
• After restart, confirmed empirically — the ∴ Thinking… narration streams live in the spinner area again. Ian pasted back verbatim content from a prior thinking block to prove it.

Token cost

• Dollars: zero. Thinking tokens are billed either way; the summarizer itself is free (adaptive thinking docs: "No charge: Tokens used to generate the summary."). Hiding the summary didn't save money — it just hid content you'd already paid for.
• Latency: small penalty. display: "omitted" (the v2.1.90 default) skips thinking-delta streaming for faster time-to-first-text; enabling summaries reintroduces the summarizer into the stream. Noticeable on short tasks, lost in the noise on long ones.
• Context & caching: unaffected. Thinking blocks aren't preserved across turns in normal conversations; prompt cache survives as long as the setting stays consistent through the session.

Net: latency for visibility, not dollars.

Not the fix (dead ends during investigation)

• Explanatory output style / its plugin — orthogonal. Controls narrative text between tool calls, not thinking visibility.
• CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING=1, /effort, MAX_THINKING_TOKENS — control thinking depth and cost, not visibility.
• Any settings.local.json outputStyle rename — unrelated; that was a separate length-limit rule issue that got conflated during investigation.

Implication

With the setting on, the thinking stream is visible to the user in real time. A user memory at ~/.claude/projects/-Users-ianmarr-projects-pai/memory/user_thinking_visible.md records this so future sessions write thinking knowing it's part of the conversation surface, not a private scratchpad.

Reference

• Claude Code Changelog — v2.1.90 entry