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 rules/andvolodko/html5-game-editor/server-securitygit clone --depth 1 https://github.com/andvolodko/html5-game-editorWhat 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 | $0.00000 | $0.00665 |
| Opus 5 | $0.00000 | $0.00332 |
| Sonnet 5 | $0.00000 | $0.00133 |
| Haiku 4.5 | $0.00000 | $0.00067 |
Grade A, and why
server-security scanned grade A with 1 finding 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 2d 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.
Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
* Never expose APIs that take absolute client paths or raw shell commands. No `child_process` / “execute command” endpoints. How it starts
The opening of the file, as written. The whole thing — 36 lines — stays where its author put it; the contents beside it link to each section on GitHub.
project-server security
Browser input is untrusted. All project filesystem access goes through ProjectService.resolveProjectPath → ProjectRootGuard.resolveSafe. Do not call path.resolve/readFile/writeFile on user-influenced paths without that guard.
Path confinement
- Resolve only project-relative paths. Reject traversal (
../, absolute inputs that escape root) viaProjectRootGuard(PATH_ESCAPE). - Do not reimplement root checks in each route. New file services (
SceneFileService,AssetDatabaseStore,AssetImportService, content serving) must takeProjectService(or the guard) as a dependency. - Never expose APIs that take absolute client paths or raw shell commands. No
child_process/ “execute command” endpoints. - Do not return internal absolute server paths in JSON error payloads meant for the browser (health may report configured root for local dev only).
Uploads and assets
- Multipart parsing (
parseAssetImportMultipart) must keep size/file-count limits (MAX_ASSET_IMPORT_FILE_BYTES/MAX_ASSET_IMPORT_FILESinimport-limits.ts). Reject non-multipart bodies. - Treat upload
filenameas untrusted: usepath.basename, then destination helpers (normalizeAssetDestination,allocateUniqueFileName). Never overwrite on name collision; allocatename-N.ext. - Import only through
AssetImportService+AssetImporterRegistry(e.g.TextureAssetImporter). Validate extension/MIME via shared helpers (isSupportedTextureExtensionfrom@game-editor/assets). Unsupported files become per-file errors, not silent writes. - Stage → commit → single manifest save; on failure roll back written files and do not leave a partial
.project/assets.jsonupdate. Keep staging under.project/import-tmp/…inside the root. - Serve bytes only for IDs present in the asset DB (
GET /assets/:id/content), after resolvingrecord.paththroughProjectService. Do not add “read any relative path” endpoints.
HTTP and persistence
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.
- 2d ago First seen · 36 lines · 0 tokens per session scan A e8347952d205
server-security is a cursor rule published in the GitHub repository andvolodko/html5-game-editor (5 stars, last pushed 7d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 665 tokens. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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