opencode-temp-sanitize

OpenCode 2 plugin that gives each project its own temporary directory.

Why

OpenCode tells every model to prefer $TMPDIR/opencode (usually /tmp/opencode) over /tmp for scratch files, and pre-approves it for external access. All projects and sessions share that one directory, so it grows without bound and nobody can tell which project left what. On hosts where /tmp is a size- or quota-limited tmpfs this eventually breaks unrelated programs.

What it does

• Creates /tmp/opencode/<slug> for the current project, where <slug> is the project directory relative to $HOME with / replaced by -, plus the CRC32 of the OpenCode project id: ~/work/example-app becomes work-example-app-1a2b3c4d. Sessions outside any project use global.
• Rewrites the core temporary-directory hint in the system prompt to point at that directory, and asks models to delete files there that they or their subagents created once those files are certainly no longer needed. The directory stays inside the pre-approved tree, so no new permission prompts.
• Sets TMPDIR to the same directory for shell commands the agent runs.
• Deletes files older than 48 hours from project directories, on startup and then hourly. "Older" means neither atime nor mtime changed in that time (mtime covers noatime mounts). Rules:
  • only regular files and symlinks are deleted; symlinks are never followed, so their targets are safe; sockets and FIFOs are left alone;
  • subdirectories are removed once empty; project directories themselves stay;
  • every project directory in /tmp/opencode is swept, so projects that are never reopened get cleaned too; loose files directly in /tmp/opencode are not touched, since OpenCode instances without this plugin put them there.

Models treat the hint as advice; nothing prevents them from writing elsewhere.

Install

Add to the plugins array in opencode.json, pinned to a version:

{
  "plugins": ["@gfn-cis/[email protected]"]
}

or straight from a git tag:

{
  "plugins": [
    "@gfn-cis/opencode-temp-sanitize@git+https://github.com/GFN-CIS/opencode-temp-sanitize.git#v0.3.0"
  ]
}

Requires OpenCode 2.

Each tag has a GitHub Release with the npm pack tarball, SHA256SUMS and a Sigstore build-provenance bundle; CI then publishes that same tarball to npm via trusted publishing (OIDC, no tokens). Verify a downloaded tarball with:

gh attestation verify gfn-cis-opencode-temp-sanitize-<version>.tgz --repo GFN-CIS/opencode-temp-sanitize

Upstream dependency

The rewrite matches the exact sentence emitted by OpenCode core in packages/core/src/instructions/builtins.ts (core/environment, verified at v2.2.6), and assumes the shared directory is path.join(os.tmpdir(), "opencode") as in packages/util/src/global-roots.ts. If upstream changes the wording, the plugin logs [temp-sanitize] tmp hint not found once per session and models fall back to the shared directory. tests/project-tmp.test.js pins the sentence.

Development

npm ci
npm run coverage   # vitest, 80% thresholds
npm run lint       # biome
npm run knip

Logic lives in src/project-tmp.js and src/sweep.js; index.js only wires OpenCode hooks and the cleanup timer.

CI runs the checks above on Node 22 and 24. Also in .github/workflows/: CodeQL (security-and-quality suite, only while the repository is public, since code scanning on private repositories needs GitHub Advanced Security), OpenSSF Scorecard, and dependency review on pull requests. Security reports: see SECURITY.md.