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.
git clone --depth 1 https://github.com/sthamann/nyx-local-aiWrote 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/rules/sthamann/nyx-local-ai/local-model-safety)<a href="https://agentmods.dev/rules/sthamann/nyx-local-ai/local-model-safety"><img src="https://agentmods.dev/badge/rules/sthamann/nyx-local-ai/local-model-safety/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/rules/sthamann/nyx-local-ai/local-model-safety"><img src="https://agentmods.dev/badge/rules/sthamann/nyx-local-ai/local-model-safety.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00000 | $0.00528 |
| Opus 5.5 | $0.00000 | $0.00211 |
| Sonnet 5.5 | $0.00000 | $0.00106 |
| Haiku 4.5 | $0.00000 | $0.00053 |
Grade A, and why
local-model-safety 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Local-model safety invariants
Special tokens never survive into persisted state
Leaked model tokens (DSML fragments, <｜end▁of▁sentence｜>) poison future
prompts: once stored in memory/sessions, models start imitating the junk.
stripSpecialTokens (src/models/client.ts) must therefore be applied at
these boundaries:
- assistant content at stream end (client.ts,
extractmode) - web-sourced tool results only (
fetch_url,web_searchin agent.ts) - memory writes and the one-time migration in
MemoryStore - stored histories in
AgentSession.loadMessages
Never sanitize file/command/MCP tool outputs (read_file, run_command,
…): the agent must see workspace content byte-faithfully — sanitizing file
reads once corrupted source that merely mentioned DSML tokens and sent a
model analyzing phantom bugs.
When adding a new boundary (new tool, new store), wire it in and add a case to
.harness/smoke.mjs.
Tool-call parsing changes require smoke tests
Any change to parsing in src/models/client.ts (JSON extraction, DSML,
function-style calls, repair) needs a matching test in .harness/smoke.mjs.
Run node .harness/smoke.mjs — it must print ALL PASS.
Other invariants
- Secrets: API keys live in
SecretStorageonly (MachineStore); never write them into settings, session files, or logs. The webview receiveshasApiKey, never the key. - File writes go through
applyWrite→WorkspaceEdit(undo/dirty-buffer safe) with checkpoint recording (recordCheckpointFile) and backups. Don't add directfs.writeFilepaths for workspace files. - Processes: anything long-running goes through
ProcessManagerso Stop (abort signal) actually kills it. No bareexecwithout a signal. - Untrusted content: anything fetched from the network is wrapped with
wrapUntrustedbefore entering the prompt;fetch_urlkeeps its SSRF guard. - Tool outputs are truncated (
truncate, 20k chars) — unbounded strings blow up the context and the session files.
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.
- 1mo ago First seen · 49 lines · 0 tokens per session scan A 4d3573eac1f4
local-model-safety is a cursor rule published in the GitHub repository sthamann/nyx-local-ai (129 stars, last pushed 3mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 528 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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