Borrowing it
Nothing to install: this file belongs to fusebase-dev/fusebase-flow. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/fusebase-dev/fusebase-flow/main/.agents/skills/app-backend/SKILL.mdgit clone --depth 1 https://github.com/fusebase-dev/fusebase-flowWrote 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.
[](https://agentmods.dev/skills/fusebase-dev/fusebase-flow/app-backend)<a href="https://agentmods.dev/skills/fusebase-dev/fusebase-flow/app-backend"><img src="https://agentmods.dev/badge/skills/fusebase-dev/fusebase-flow/app-backend/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/fusebase-dev/fusebase-flow/app-backend"><img src="https://agentmods.dev/badge/skills/fusebase-dev/fusebase-flow/app-backend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 6 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Privilege Escalation · line 382 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
- high Privilege Escalation · line 798 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
- high Privilege Escalation · line 820 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
- medium Server-Side Request Forgery · line 76 Code issues a request to a loopback, link-local, or private-range host. This can reach internal services not meant to be exposed and is a common SSRF pivot.Fix: Avoid requests to loopback/link-local/private hosts from skill code. If internal access is intended, document it and validate the target against an allowlist.
- medium Excessive Agency · line 381 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
- medium Excessive Agency · line 926 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00092 | $0.11978 |
| Opus 5.5 | $0.00037 | $0.04791 |
| Sonnet 5.5 | $0.00018 | $0.02396 |
| Haiku 4.5 | $0.00009 | $0.01198 |
Grade A, and why
app-backend 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 2mo 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
When the app needs to receive webhooks from a third-party service (Asana, GitHub, Stripe, Monday, etc.), register the subscription with that provider **yourself** as part of the deploy — do not hand the user a `curl` / a Copies of this mod
1 near-identical copy found in the catalogue:
- app-backend — 97% identical, 8 lines differ
How it starts
The opening of the file, as written. The whole thing — 976 lines — stays where its author put it; the contents beside it link to each section on GitHub.
App Backend
Multi-User Architecture
Apps are always multi-user. The backend serves requests from many users concurrently. Every design decision must account for this.
Per-user vs. shared state:
| Storage | Scope | Use for |
|---|---|---|
| httpOnly cookies | Per-user (per browser) | OAuth tokens, user preferences, session data |
| Dashboard rows (keyed by user ID) | Per-user (persistent) | User settings, saved state |
| Fusebase secrets / env vars | Shared (all users) | API keys, service-account credentials |
| In-memory variables | Shared (all users, lost on restart) | Short-lived caches only |
Common mistakes:
- ❌ Storing a user's OAuth token in an env var or in-memory config → all users share one token
- ❌ Storing a user's preference in a module-level variable → last user's preference wins for everyone
- ❌ Using env vars for per-user settings or selections → same value for everyone
- ❌ Using session/token-derived values (
ft:*, JWT pieces, rotating token IDs) as persistent row partition keys - ✅ Store per-user data in cookies or dashboard rows keyed by user
- ✅ Use env vars only for credentials/config shared across all users (e.g. OAuth client ID/secret)
Stable key as partition key (required)
For any persisted per-user data, derive the partition key from stable identity only:
- Use
userId/orgUserIdfrom a stable identity endpoint (getMe-style call) - Normalize to a canonical key (example:
user:<userId>) in one helper - Use the same key on all read/write paths
Do not derive partition keys from runtime app/session tokens. Tokens rotate, so token-derived keys cause "missing records after relogin" while data still exists under old keys.
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.
- 2mo ago First seen · 976 lines · 92 tokens per session scan A 137e7b07cb35
app-backend is a skill published in the GitHub repository fusebase-dev/fusebase-flow (9 stars, last pushed 13d ago), licensed MIT. It adds 92 tokens to every session and 11,978 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
app-backend compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| app-backendfusebase-dev/fusebase-flow | Skill | 9 | 13d ago | MIT | A | 92 | Claude Code |
| adobe-express-cors-and-backendSandgrouse/adobe-express-dev-skill | Skill | 9 | 2mo ago | none | A | 92 | Claude Code, Codex |
| adobe-express-oauth-authenticationSandgrouse/adobe-express-dev-skill | Skill | 9 | 2mo ago | none | A | 50 | Claude Code, Codex |
| lov-optimize-tauri-backendlovstudio/skills | Skill | 72 | yesterday | MIT | A | 71 | Claude Code |
| lov-cli-creatorlovstudio/skills | Skill | 72 | yesterday | MIT | A | 58 | Claude Code |
| lov-api-creatorlovstudio/skills | Skill | 72 | yesterday | MIT | A | 75 | Claude Code |
| lov-cli2anythinglovstudio/skills | Skill | 72 | yesterday | MIT | A | 55 | Claude Code |