Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/TrNgTien/vfsnpx agentmods add rules/trngtien/vfs/vfs-agent-searchWrote 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/trngtien/vfs/vfs-agent-search)<a href="https://agentmods.dev/rules/trngtien/vfs/vfs-agent-search"><img src="https://agentmods.dev/badge/rules/trngtien/vfs/vfs-agent-search/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/trngtien/vfs/vfs-agent-search"><img src="https://agentmods.dev/badge/rules/trngtien/vfs/vfs-agent-search.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 | $0.02999 | $0.02999 |
| Opus 5.5 | $0.01200 | $0.01200 |
| Sonnet 5.5 | $0.00600 | $0.00600 |
| Haiku 4.5 | $0.00300 | $0.00300 |
Grade A, and why
vfs-agent-search 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 — 264 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Search Strategy: Navigate with vfs, Understand with Grep/Read
vfs is a navigation tool (find where things are), not an understanding tool (know how things work). Signatures without bodies create false confidence. Always read implementation before claiming to understand behavior.
How vfs Works
vfs parses source files via AST and returns exported signatures with bodies stripped. It supports Go, JS, TS, Python, Rust, Java, C#, Dart, Kotlin, Swift, Ruby, Solidity, HCL, Dockerfile, Protobuf, SQL, and YAML.
What vfs gives you: internal/services/fare.go:42: func CalculateFare(req *FareRequest) (*FareResponse, error)
What vfs hides: The 50 lines of implementation inside that function.
This makes vfs excellent for locating definitions, but dangerous for understanding behavior.
Step 1: Classify Your Intent
Before searching, determine what you need:
| Intent | Description | Primary tool | Depth required |
|---|---|---|---|
| Locate | "Which file defines X?" | vfs | Signature only — no Read needed |
| Understand | "How does X work?" | vfs → Read body + context | Full implementation + dependencies |
| Modify | "Change how X behaves" | vfs → Read body + callers | Full implementation + Grep for usages |
| Debug | "Why does X fail?" | Grep + Read | Bodies, callers, error paths — vfs alone is useless here |
Step 2: Search (vfs for navigation)
Use vfs as the first step to locate definitions — not as the final answer.
Access Priority: MCP First, CLI Fallback
MCP runs on the host outside the sandbox and bypasses binary restrictions.
Step,Name,Action,Condition,Result
1,MCP,"CallMcpTool(server: user-user-vfs, toolName: search, ...)",success,Use MCP for all vfs operations
1,MCP,"CallMcpTool(server: user-user-vfs, toolName: search, ...)",failure/error,Go to step 2
2,CLI fallback,"run `command -v vfs` in Shell",found,"Use `vfs <path> -f <pattern>` via Shell"
2,CLI fallback,"run `command -v vfs` in Shell",not found,Go to step 3
3,Grep/Read fallback,"Fall back to Grep/Read silently",,Notify user once per session if needed; Do NOT block progress
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 · 264 lines · 2,999 tokens per session scan A d16c7edd21d6
vfs-agent-search is a cursor rule published in the GitHub repository TrNgTien/vfs (143 stars, last pushed 1mo ago), licensed MIT. It adds 2,999 tokens to every session, about $0.0120 per session on Opus 5.5. 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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