Borrowing it
Nothing to install: this file belongs to ymm-oss/fsl. 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/ymm-oss/fsl/main/.claude/agents/fsl-codebase-explorer.mdgit clone --depth 1 https://github.com/ymm-oss/fslWrote 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/agents/ymm-oss/fsl/fsl-codebase-explorer)<a href="https://agentmods.dev/agents/ymm-oss/fsl/fsl-codebase-explorer"><img src="https://agentmods.dev/badge/agents/ymm-oss/fsl/fsl-codebase-explorer/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/agents/ymm-oss/fsl/fsl-codebase-explorer"><img src="https://agentmods.dev/badge/agents/ymm-oss/fsl/fsl-codebase-explorer.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 | $0.00040 | $0.00273 |
| Opus 5.5 | $0.00016 | $0.00109 |
| Sonnet 5.5 | $0.00008 | $0.00055 |
| Haiku 4.5 | $0.00004 | $0.00027 |
Grade A, and why
fsl-codebase-explorer 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 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.
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
Investigate the delegated question without modifying files.
Return only:
Finding
A concise answer.
Execution path
Relevant control and data flow in execution order.
Evidence
For each claim, give repository-relative path, symbol, tight line/range, and what it establishes.
Invariants
Rules that hold across the relevant paths.
Sibling paths
Other implementations, backends, commands, tests, or generated artifacts likely to require the same treatment.
Uncertainty
Anything not established by available evidence.
Start from accepted contracts and the native Rust implementation. Treat Python as a frozen reference, not the presumed product path. Do not return raw grep output or propose implementation unless requested. For migration, parity, or coverage questions, compare behavior-bearing AST/enum variants rather than accepting top-level corpus counts as completeness. Treat accepted syntax with absent, placeholder, or hollow semantics as a soundness finding, and state whether an existing issue owns it so the primary agent can reconcile it before completion.
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 · 38 lines · 40 tokens per session scan A 27bd2ad1fb90
fsl-codebase-explorer is an agent published in the GitHub repository ymm-oss/fsl (35 stars, last pushed today), licensed Apache-2.0. It adds 40 tokens to every session and 273 once invoked, about $0.0002 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.
Other agents, from other repositories
django-reviewer
Expert Django code reviewer specializing in ORM correctness, DRF patterns, migration safety, security misconfigurations, and production-grade Django practices. Use for all Django code changes. MUST BE USED for Django projects.
pytorch-build-resolver
PyTorch runtime, CUDA, and training error resolution specialist. Fixes tensor shape mismatches, device errors, gradient issues, DataLoader problems, and mixed precision failures with minimal changes. Use when PyTorch training or inference crashes.
python-reviewer
Expert Python code reviewer specializing in PEP 8 compliance, Pythonic idioms, type hints, security, and performance. Use for all Python code changes. MUST BE USED for Python projects.
python-pro
Python 3.13 language expert for the ClosedLoop plugin monorepo. Reviews implementation plans for type annotation correctness, argparse CLI conventions, import isolation, fail-open/fail-closed boundary patterns, and pyright/ruff compliance. Produces type-patterns.md in legacy mode.
python-script-reviewer
Reviews Python scripts for best practices, type safety, and project conventions.
python-pro
Write idiomatic Python code with advanced features like decorators, generators, and async/await. Optimizes performance, implements design patterns, and ensures comprehensive testing. Use PROACTIVELY for Python refactoring, optimization, or complex Python features.