nexus-storage

nexus-storage is a skill for Claude Code, Codex from ProfSynapse/nexus. It costs 65 tokens per session (708 once invoked), scanned A, original, MIT.

Storage guidance for Nexus, where permanent event records and rebuildable SQLite data serve different purposes. It explains how to change the schema, save data across restarts, and investigate storage problems.

In plain words
What is it for?
Use it when adding tables or columns, persisting new data, resolving storage paths, or diagnosing missing, outdated, duplicated, slow, or vanished data.
Why use it?
It prevents data loss caused by writing to the wrong store, using SQLite as the source of truth, or reading before the cache is ready.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/profsynapse/nexus/nexus-storage
Any agent
npx skills add ProfSynapse/nexus --skill nexus-storage
Clone the repo
git clone --depth 1 https://github.com/ProfSynapse/nexus

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for nexus-storage

README.md
[![agentmods](https://agentmods.dev/badge/skills/profsynapse/nexus/nexus-storage.svg)](https://agentmods.dev/skills/profsynapse/nexus/nexus-storage)
Your own site
<a href="https://agentmods.dev/skills/profsynapse/nexus/nexus-storage"><img src="https://agentmods.dev/badge/skills/profsynapse/nexus/nexus-storage.svg" alt="Measured on agentmods" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 708 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00065 $0.00708
Opus 5 $0.00032 $0.00354
Sonnet 5 $0.00013 $0.00142
Haiku 4.5 $0.00006 $0.00071

Measured 3d ago against content hash 74e1644b6d6a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nexus-storage 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 3d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/check_schema_consistency.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/nexus-storage/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Nexus Storage

Nexus stores data twice on purpose. The sharded JSONL event store is the source of truth; SQLite is a cache that is deleted and replayed on demand. Almost every storage bug in this repo is a write that landed on the wrong side of that line, or a read that ran before the cache was ready.

This router points at the procedure for your job. Working from the router alone is how the three-place schema change becomes a two-place one.

Workflow

  1. Pick the job and open its protocol before editing anything:

    Your job Protocol
    Add or change a SQLite table, column or index protocols/change-schema.md
    Persist a new kind of data, or make a write survive restart protocols/persist-new-data.md
    Data is missing, stale, duplicated, slow, or vanished after a rebuild protocols/diagnose-storage.md
  2. Read references/storage-model.md before writing any persistence code. It states the three invariants that decide whether a design is legal here. A change that breaks one is a data-loss bug that unit tests will happily pass.

  3. NEVER hardcode a storage root, and NEVER treat SQLite as authoritative. Resolve roots through the resolvers named in references/paths-and-layout.md, and write through a repository so the event lands in JSONL first.

  4. If you touched SchemaMigrator.ts or schema.ts, run scripts/check_schema_consistency.py from the repo root and treat a non-zero exit as a stop:

    python3 .claude/skills/nexus-storage/scripts/check_schema_consistency.py .
    
  5. Verify at runtime, not just statically. Every protocol here ends in a verification step that a static check cannot substitute for — schema changes fail on the upgrade path and the fresh-install path independently, and cache bugs only appear after a real rebuild.

  6. At the end of a session that used this skill, run protocols/self-refine.md.

Map

  • protocols/ — the procedures: change-schema, persist-new-data, diagnose-storage, self-refine.
  • references/ — read on demand: storage-model.md (invariants and rebuild semantics), paths-and-layout.md (roots, resolvers, on-disk shapes, cache backends), schema-rules.md (what a migration may and may not do), failure-modes.md (symptom → cause → fix).
  • scripts/check_schema_consistency.py — proves the three schema definitions agree. Run it; do not eyeball them.

Read the full file on GitHub · 60 lines

Changes

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.

  1. 3d ago First seen · 60 lines · 65 tokens per session scan A 74e1644b6d6a

Subscribe to this mod's changes

nexus-storage is a skill published in the GitHub repository ProfSynapse/nexus (154 stars, last pushed 3d ago), licensed MIT. It adds 65 tokens to every session and 708 once invoked, about $0.0003 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 2026-08-30.

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