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/modelengine-group/nexent/environment_variablegit clone --depth 1 https://github.com/ModelEngine-Group/nexentWhat 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 | $0.00408 |
| Opus 5 | $0.00000 | $0.00204 |
| Sonnet 5 | $0.00000 | $0.00082 |
| Haiku 4.5 | $0.00000 | $0.00041 |
Grade A, and why
environment_variable 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 yesterday.
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.
What it actually says
Environment Variables: Single Source of Truth
All environment variable access must go through backend/consts/const.py. No direct os.getenv() or os.environ.get() calls elsewhere.
Do
# backend/consts/const.py
APPID = os.getenv("APPID", "")
TOKEN = os.getenv("TOKEN", "")
# other modules
from consts.const import APPID, TOKEN
Don't
# direct calls in other modules
import os
appid = os.getenv("APPID")
token = os.environ.get("TOKEN")
Architecture
- Single source: Only
backend/consts/const.pymay read env vars. - SDK (
sdk/): Never read env. Accept configuration via parameters. Removefrom_env(). - Services (
backend/services/): Read fromconsts.const; pass config to SDK. - Apps (
backend/apps/): Read fromconsts.const; pass through to services/SDK. No business logic here.
Migration checklist
- Add new vars to
backend/consts/const.py. - Update
.env.example. - Remove all direct
os.getenv()/os.environ.get()outsideconst.py. - Import from
consts.constin backend modules. - Pass configuration as parameters to SDK.
- Remove
from_env()methods from config classes. - Update service constructors to read from
const.py.
Validation
- No direct env access outside
const.py. - No
from_env()in config classes. - All env vars defined in
const.py. - SDK modules accept configuration via parameters.
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.
- yesterday First seen · 47 lines · 0 tokens per session scan A 453c1fecf886
environment_variable is a cursor rule published in the GitHub repository ModelEngine-Group/nexent (5,841 stars, last pushed 3d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 408 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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