Claude Code vs Codex in Obsidian: Which Agent Fits Your Vault
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Both Claude Code and Codex can read, search and edit an Obsidian vault, because a vault is a plain folder of Markdown files. The biggest difference is the account you already have. Codex comes with every ChatGPT plan, including Free. Claude Code needs a paid Claude plan, from Pro at $20 a month. Past that, they differ in how they ask before changing notes and in which instruction file they read.
You don't have to choose for good. The free SystemSculpt plugin, which we make, runs either one in a chat pane inside Obsidian on desktop, with your own login, and you can switch per chat.
Checked on November 3, 2026, against Claude Code 2.1.316, Codex CLI 0.166.0, both vendors' pricing and docs, and SystemSculpt 6.18.10.
Claude Code and Codex side by side
| Claude Code | Codex | |
|---|---|---|
| Made by | Anthropic | OpenAI |
| Plans that include it | Pro $20 a month ($17 billed yearly), Max $100, Ultra $200, Team, Enterprise; or an API account | ChatGPT Free, Go $8 a month, Plus $20, Pro from $100, Business, Edu, Enterprise; or an API key |
| Instruction file in the vault | CLAUDE.md (reads AGENTS.md when there's no CLAUDE.md) | AGENTS.md |
| Block files or folders | Deny rules in .claude/settings.json | Sandbox: read-only or workspace-write limited to the folder |
| Default model | Opus 5.5 on paid plans | A recommended model from your Codex install |
| Source code | Not open source | Open source, Apache-2.0 |
| Runs on | macOS, Windows, Linux | macOS, Windows, Linux |
| Phone or tablet | No | No |
| In Obsidian with SystemSculpt | Yes, desktop, free | Yes, desktop, free |
Plan prices are the vendors' US list prices on November 3, 2026. Usage limits differ by plan; check each vendor's page before you buy.
Which one fits your vault
Pick Codex if you already pay for ChatGPT, or want to try an agent on your notes without a new subscription. Its sandbox keeps writes inside the vault folder by default in SystemSculpt, and its Read only mode lets it read every note without changing any.
Pick Claude Code if you already have a paid Claude plan, or you want a Plan only mode that proposes changes before making any. Deny rules let you wall off single folders, such as Private/ or .obsidian/.
Use both if you have both accounts. Many tasks, such as tidying an inbox folder or summarizing a project, work the same in either. Keep the rules in one AGENTS.md so both agents follow them, as shown below.
How each one asks before changing notes
In SystemSculpt, you choose a mode in the run line below the message box. Each mode maps to the agent's own safety controls:
| SystemSculpt mode | Claude Code | Codex |
|---|---|---|
| Auto (new-chat default) | Runs safe actions without asking. Claude Code's safety check blocks risky ones. | Works inside the vault. Codex's reviewer only asks you about unsafe actions. |
| Ask first | Ask before edits: asks before every edit and command | Ask: works inside the vault, asks before editing other files or using the internet |
| Edit freely | Accept edits: edits notes without asking, asks before commands | No separate mode |
| Look, don't touch | Plan only: reads and plans, changes nothing until you approve the plan | Read only: reads your vault without changing it |
| Your own config | Claude Code settings | Codex settings |
SystemSculpt never turns on Claude Code's permission-bypass mode or Codex's full-access sandbox. When either agent asks, the request and the change show inline in the chat, and you approve or decline there.
In a terminal, the defaults differ. Codex recommends read-only in a folder that isn't a Git repository, which most vaults aren't, so you may need to allow writes. Claude Code asks before edits unless you change its mode with Shift+Tab.
Instruction files: CLAUDE.md and AGENTS.md
Both agents read a file of standing instructions from the folder they start in. For a vault, that is where you describe your folders and rules, such as "Archive/ is read only" or "never rename a note without asking".
- Claude Code reads
CLAUDE.md. If there is noCLAUDE.md, it readsAGENTS.md. - Codex reads
AGENTS.md, up to 32 KiB by default.
To keep one set of rules for both, write them in AGENTS.md at the vault root. Claude Code picks it up as long as you have no CLAUDE.md, or you can add a CLAUDE.md containing @AGENTS.md to import it. Claude Code and your Obsidian vault has a sample file and deny rules for private folders.
Run either one in Obsidian
1. Install and sign in to the agent. Install Claude Code or Codex, then sign in once in a terminal: run claude and type /login, or run codex login.
2. Install SystemSculpt. In Obsidian, open Settings, then Community plugins, then Browse. Search for SystemSculpt, then select Install and Enable. Or use the SystemSculpt page in the Obsidian plugin directory. The welcome screen offers a free account for hosted features; you can choose Explore on my own.
3. Open chat and pick the agent. Select Open chat in the left ribbon. In the run line below the message box, choose Claude Code or Codex. If you have both and haven't picked one yet, a new chat picks the one you used more in the last 30 days. Switching starts a new chat; the old one stays in your history.
SystemSculpt starts the agent with its working folder at the vault root, using your own login and settings. It doesn't send the open note unless you add it with Add current note or Add notes from vault…. Each chat is saved as a Markdown note in your vault, in SystemSculpt/Chats by default.
The setup guides go further: Claude Code in Obsidian and Codex in Obsidian.
What leaves your computer
Claude Code sends your messages and the notes it reads to Anthropic through your Claude account. Codex sends them to OpenAI through your ChatGPT account or API key. In SystemSculpt, these chats don't go through SystemSculpt's servers or use its credits, and the plugin doesn't read either agent's credentials.
Common questions
Is Claude Code or Codex better for Obsidian? Neither is better for every vault. Codex is the cheaper start because it comes with every ChatGPT plan. Claude Code has a Plan only mode and per-folder deny rules. Both edit Markdown notes well, and SystemSculpt runs either.
Can I use Codex in Obsidian for free? Codex is included in ChatGPT Free, within its usage limits, and SystemSculpt is a free plugin. So yes, with a free ChatGPT account on desktop.
Is Claude Code free? No. The free Claude plan doesn't include Claude Code. It starts with Pro at $20 a month.
Do I need a SystemSculpt account? No. Claude Code and Codex in SystemSculpt use your own logins. A free account is only for SystemSculpt's hosted features, such as audio transcription and related-note search.
Do they work on Obsidian mobile? No. Both run on a desktop computer. On a phone or tablet, SystemSculpt's chat uses its hosted AI instead.
What about Gemini CLI? SystemSculpt doesn't run it, and since June 18, 2026 it no longer serves free or Google AI Pro accounts. See Gemini CLI in Obsidian.
Install SystemSculpt from the Obsidian plugin directory, then choose Claude Code or Codex in the chat run line.