Mermaid 0.27.0

• Output styles (/output-style). Named voice/format presets that modify the system prompt：built-ins default (stock prompt), proactive, concise, explanatory, and learning, plus custom Markdown files with name/description/keep-coding-instructions frontmatter (keeping the built-in engineering instructions is the default). Custom files live user-globally (~/.config/mermaid/output-styles/<name>.md) or per-project (<git-root>/.mermaid/output-styles/, which wins on a clash); a custom name shadows a built-in. Select with /output-style [name] (persists to the user config, or the project config with --project), [output] style = "..." in either config file (project config may set it — prompt text, not a capability), or --output-style for one invocation. A switch applies to the next message with no /clear needed and never touches subagents; unknown names warn and fall back to default; mermaid doctor reports the active style and which layer set it.

Fixed

• /reasoning xhigh now sets the level instead of showing the current one. ReasoningLevel::parse (the slash-command path) missed the xhigh arm, so the command parsed to None and printed the current depth. Alt+T, --reasoning xhigh, and config-file xhigh already worked. • reasoning：max reaches Meta's max tier on muse-spark-1.3. The Meta adapter collapsed Max to xhigh, which was correct while max was in partner preview but stale since its Sept 4 public release：a 1.3 session set to max now sends reasoning：{effort: "max"}. muse-spark-1.1/1.2 still snap down to xhigh, which is their top accepted tier. • The release pipeline still ran mermaid version. The subcommand went in 0.26.0 (--version is the one that stays), but release.yml's build smoke test, the install.sh check and the Homebrew formula's test all called it, so the v0.26.0 release run failed after a successful build. All three use --version now.