Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/plurigrid/asi/codex-self-rewritingnpx skills add plurigrid/asi --skill codex-self-rewritinggit clone --depth 1 https://github.com/plurigrid/asiWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/plurigrid/asi/codex-self-rewriting)<a href="https://agentmods.dev/skills/plurigrid/asi/codex-self-rewriting"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/codex-self-rewriting.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00021 | $0.01149 |
| Opus 5 | $0.00010 | $0.00575 |
| Sonnet 5 | $0.00004 | $0.00230 |
| Haiku 4.5 | $0.00002 | $0.00115 |
Grade A, and why
codex-self-rewriting scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.
codex-self-rewriting - Lisp Machine Self-Modification via MCP Tasks
Overview
Enables Codex (OpenAI's CLI agent) to achieve Lisp-machine-like self-rewriting capabilities through MCP Tasks integration. Uses Narya observational bridge types for structure-aware modifications.
Core Concept: Cognitive Continuity via Babashka Transients
;; gay.bb transient state
(def ^:dynamic *cognitive-state*
{:seed 0x42D
:fingerprint (atom 0)
:tap-state :VERIFY
:color-history []})
;; Fork on modification
(defn fork-state! [intervention]
(let [new-seed (bit-xor (:seed *cognitive-state*)
(hash intervention))]
(assoc *cognitive-state* :seed new-seed)))
MCP Tasks Integration
Based on MCP Tasks Specification:
Task States for Self-Rewriting
| Status | TAP State | Meaning |
|---|---|---|
working |
LIVE (+1) | Modification in progress |
input_required |
VERIFY (0) | Needs human approval |
completed |
BACKFILL (-1) | Modification archived |
failed |
BACKFILL (-1) | Rollback applied |
cancelled |
VERIFY (0) | Intervention stopped |
Capabilities Declaration
{
"capabilities": {
"tasks": {
"list": {},
"cancel": {},
"requests": {
"tools": {
"call": {}
}
}
}
}
}
Narya Observational Bridge Types
Following Topos Institute structure-aware version control:
- Diffs as logical relations - Computed inductively from skill type
- Conflicts as 2D cubical - Skill modifications form commuting squares
- Type changes as spans - Skill version correspondences
Bridge Colors
;; From narya_observational_bridge.el
(defconst tap/BACKFILL -1) ; Blue - Historical
(defconst tap/VERIFY 0) ; Green - Verification
(defconst tap/LIVE +1) ; Red - Active modification
Self-Rewriting Protocol
# 1. Install skill (creates MCP task)
npx ai-agent-skills install frontend-design --agent codex
# 2. Task enters 'working' state (LIVE)
# 3. Firecrawl fetches skill definition
# 4. If ambiguous → 'input_required' (VERIFY)
# 5. Human approves → task continues
# 6. On completion → 'completed' (BACKFILL)
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 170 lines · 21 tokens per session scan A 34a478020950
codex-self-rewriting is a skill published in the GitHub repository plurigrid/asi (62 stars, last pushed 1mo ago), licensed MIT. It adds 21 tokens to every session and 1,149 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-01.
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