principle-separate-before-serializing-shared-state
About principle-separate-before-serializing-shared-state
A development skill for handling mutable state shared by concurrent actors. It recommends eliminating shared write targets when possible, and using structural serialization when a shared target is truly required.
Key features
- 01Identify shared mutable state
- 02Separate independent write targets
- 03Merge at reporting boundaries
- 04Serialize writes when sharing is required
- 05Treat locking as a design signal
Use cases
- 01Preventing concurrent file-write races
- 02Designing state ownership for multiple workers
- 03Choosing serialization for a canonical shared object
Install
Copy the command and run it in a terminal.
npx skills add https:/After installing, type/principle-separate-before-serializing-shared-statein Claude Code to confirm it loaded.
Bundled filesLICENSE
Details
From the project READMESeparate Before Serializing Shared State
When concurrent actors might share mutable state, first ask whether they need the same mutable object. If not, eliminate the sharing. When sharing is real, enforce serialization structurally: lockfiles, sequential phases, exclusive ownership. Instructions and conventions are not concurrency control.
Why: Concurrent writes to shared state create race conditions that are intermittent, hard to reproduce, and expensive to debug.
Pattern:
- Identify shared mutable state (files both read and write, branches both push to, APIs both define and consume).
- Default: eliminate the shared write target. Ask: do these actors need one canonical object, or are they publishing independent facts? Give each actor its own owned file, key, branch, or state directory, and merge only at the read/reporting boundary. Two workers writing their own
lastXfield into onestate.jsonis still shared mutation.indexer-state.json+metrics-state.jsonis not. - Only when one shared write target is a real invariant, serialize access structurally (lockfiles, sequential phases, single-writer actor, or atomic compare-and-swap). Treat "we need a lock" as a design smell to check, not as the default answer.