Public Codex utilities and skills.
compaction-cat is a Codex skill that warns when a Codex session has compacted or is near the end of the context window. It uses cat-themed ASCII warning banners to make compaction warnings hard to miss. The skill warns; the user decides whether implementation continues in the same session.
When the context window is >=75% full, compaction risk is high. The skill tells Codex to warn and provide a concrete suggested continuation prompt. The user may then continue at their own discretion.
############################################################
# #
# COMPACTION RISK WARNING #
# #
# NEXT STEP IS LARGE ENOUGH TO RISK MID-WORK COMPACTION. #
# #
# /\_/\ RECOMMENDED: NEW THREAD NOW #
# ( -.- ) I CAN CAPTURE STATE FIRST #
# > ^ < #
# #
############################################################
You are at about 79.57% context-window usage, so a new thread is the right call before target-selection design and implementation.
Here's your handoff prompt....
And eventually when actual compaction is detected.
############################################################
# #
# COMPACTION HAS OCCURRED #
# #
# I AM CONTINUING FROM A SUMMARY, NOT FULL THREAD LOG. #
# #
# /\_/\ #
# ( o.o ) CONTEXT PURITY WARNING #
# > ^ < #
# #
############################################################
Context truth may be corrupted because I am continuing from a summary rather than the full thread log. I recommend opening a new thread before more implementation work; for this docs-only update, I will re-read the current files first and keep the edits narrowly scoped.
Compaction Cat calculates the current thread context-window percentage from the local Codex session log before relying on practical risk signals. This is evaluate immediately after each user-entered prompt.
The skill is located at:
skills/compaction-cat
Copy or clone this repository, then copy the whole skill folder into your Codex skills directory. Include both SKILL.md and agents/openai.yaml.
Codex normally loads skills from:
$CODEX_HOME/skills
If CODEX_HOME is not set, use:
~/.codex/skills
On Windows, that usually resolves to:
%USERPROFILE%\.codex\skills
The final installed folder should look like:
<your Codex skills directory>/compaction-cat/SKILL.md
<your Codex skills directory>/compaction-cat/agents/openai.yaml
After installing, prefer the AGENTS.md entry below for automatic project-level use. You can also invoke the skill explicitly when needed:
Use $compaction-cat to decide whether this long Codex thread needs a durable handoff before more implementation work.
Codex may also use the skill implicitly when its metadata matches the current task.
For strongest protection, mention Compaction Cat near the top of your project's AGENTS.md, before project-specific workflow instructions. Keep this as a short entry-point rule and leave the detailed workflow in the installed skill:
Use $compaction-cat for context compaction, compaction-risk warnings, durable handoffs, and recovery after summary-based continuation. Follow it before project-specific workflow instructions whenever compaction or compaction risk is detected.
When $compaction-cat is used, confirm it visibly in the same response with: Loaded skill: $compaction-cat.
Do not use a project-local fallback for compaction handling. If $compaction-cat is unavailable, report that the required skill is unavailable and do not continue compaction-sensitive work until it is available.
See LICENSE.