Use this skill for non-trivial work in this repository or any project where UltraThink is installed.
Contract
Read AGENTS.md for the active Codex instructions.
Check .ckignore before broad file exploration.
Use VFS/code-intel before full file reads when those tools are available.
Route to the full skill mesh only on demand:
registry: .claude/skills/_registry.json
skill bodies: .claude/skills/<name>/SKILL.md
Keep user/developer/system instructions above UltraThink when there is a conflict.
For substantial multi-step work, create or update a Markdown task ledger and mark tasks complete as they land. See docs/protocols/task-ledger.md.
Preserve unrelated worktree changes.
Before ending substantial work, write a .handoff/handoff-<DD-mon-YYYY>-<HHMM>.md file.
Why This Skill Is Small
Codex has a startup skill-description budget. Do not expose every UltraThink skill directly in .agents/skills; that causes budget warnings and omitted skills. This facade keeps Codex startup small while preserving on-demand access to the complete .claude/skills mesh.
1---2name: inugamidev-ultrathink-ultrathink-core3description: UltraThink Core4---56# UltraThink Core78Use this skill for non-trivial work in this repository or any project where UltraThink is installed.910## Contract11121. Read `AGENTS.md` for the active Codex instructions.132. Check `.ckignore` before broad file exploration.143. Use VFS/code-intel before full file reads when those tools are available.154. Route to the full skill mesh only on demand:16 - registry: `.claude/skills/_registry.json`17 - skill bodies: `.claude/skills/<name>/SKILL.md`185. Keep user/developer/system instructions above UltraThink when there is a conflict.196. For substantial multi-step work, create or update a Markdown task ledger and mark tasks complete as they land. See `docs/protocols/task-ledger.md`.207. Preserve unrelated worktree changes.218. Before ending substantial work, write a `.handoff/handoff-<DD-mon-YYYY>-<HHMM>.md` file.2223## Why This Skill Is Small2425Codex has a startup skill-description budget. Do not expose every UltraThink skill directly in `.agents/skills`; that causes budget warnings and omitted skills. This facade keeps Codex startup small while preserving on-demand access to the complete `.claude/skills` mesh.2627---28> Source: [InugamiDev/ultrathink](https://github.com/InugamiDev/ultrathink) — distributed by [TomeVault](https://tomevault.io).29<!-- tomevault:4.0:skill_md:2026-06-16 -->
Run npx skillmds@latest add tomevault-io/inugamidev-ultrathink-ultrathink-core in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.
UltraThink Core It is listed under Coding & Dev Tools on SkillMD.
This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.
This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.
Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.
tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.
tomevault-io