Backend Reference

A read-only guide to the server-side rules that frontend code relies on, including URLs, APIs, login, storage layers, and module lookup.

In plain words
What is it for?
Use it when frontend work needs to call APIs, follow routing rules, check login requirements, or understand where modules and user files are found.
Why use it?
It helps an agent understand how the application handles requests and authentication without treating backend files as safe to edit.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/binary16labs/prime-silo/backend-reference
Any agent
npx skills add binary16labs/prime-silo --skill backend-reference
Clone the repo
git clone --depth 1 https://github.com/binary16labs/prime-silo

Made for: Claude Code, Codex.

Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,470 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00029 $0.01470
Opus 5 $0.00015 $0.00735
Sonnet 5 $0.00006 $0.00294
Haiku 4.5 $0.00003 $0.00147

Measured 2d ago against content hash 0137fc83f230, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Backend Reference scanned grade A with 0 findings 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to Backend Reference — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

app/L0/_all/mod/_core/skillset/ext/skills/development/backend-reference/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Use this skill when frontend work depends on understanding backend behavior. This skill is read-only context, not authorization to change backend files.

Hard Boundary

  • Do not edit server/, commands/, or packaging/ from this skill set.
  • If the task truly requires backend changes, stop and ask instead of treating this skill as permission.
  • Backend changes are non-standard in this project. Only ask for them when frontend-only work cannot safely enforce security, integrity, cross-user isolation, or runtime stability.
  • When you ask, explain why the frontend solution would be insufficient and describe the narrow backend change required.

Page And Request Flow

Current request order is:

  1. API preflight handling
  2. /api/proxy
  3. /api/<endpoint>
  4. /mod/...
  5. /~/... and /L0/..., /L1/..., /L2/...
  6. page shells and page actions

The browser app mounts through page shells in server/pages/. /login is public. / and /admin require authentication.

API Families

Important frontend-facing endpoint families are:

  • app files: file_list, file_paths, file_read, file_write, file_delete, file_copy, file_move, file_info, folder_download
  • local history: git_history_list, git_history_diff, git_history_preview, git_history_rollback, git_history_revert
  • modules: module_list, module_info, module_install, module_remove
  • runtime and identity: extensions_load, password_generate, password_change, user_crypto_session_key, user_self_info

These endpoints are thin wrappers over shared helpers in server/lib/customware/ and server/lib/auth/.

file_write still defaults to whole-file replacement, but it also supports operation: "append", "prepend", and "insert". Insert writes accept exactly one anchor through line, before, or after, use the first literal before or after match, treat line as a 1-based insertion point, and require utf8.

file_list and file_paths support access: "write" or writableOnly: true for writable-only discovery. They also support gitRepositories: true; with a pattern such as **/.git/, file_paths returns local-history owner roots like L1/team/ and L2/alice/ without exposing reserved .git metadata paths.

Read the full file on GitHub · 84 lines

Changes

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.

  1. 2d ago First seen · 84 lines · 29 tokens per session scan A 0137fc83f230

Subscribe to this mod's changes

Backend Reference is a skill published in the GitHub repository binary16labs/prime-silo (5 stars, last pushed 9d ago), licensed MIT. It adds 29 tokens to every session and 1,470 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to Backend Reference, differing in 0 lines, and is treated as a copy.