BitFun is a desktop AI agent that turns tasks into interactive mini-apps while also writing code, creating documents, and controlling computers. It is for software development and general desktop work across Windows, macOS, and Linux. Its catalogue entries extend the agent with skills, agents, and instructions.
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 skills add GCWing/BitFun --skill gstack-reviewgit clone --depth 1 https://github.com/GCWing/BitFunWrote 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/skills/gcwing/bitfun/gstack-review)<a href="https://agentmods.dev/skills/gcwing/bitfun/gstack-review"><img src="https://agentmods.dev/badge/skills/gcwing/bitfun/gstack-review/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/skills/gcwing/bitfun/gstack-review"><img src="https://agentmods.dev/badge/skills/gcwing/bitfun/gstack-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high System Prompt Leakage · line 298 Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.Fix: Remove any instructions that reveal, print, or output system prompts or internal rules. System instructions should never be exposed to end users.
- medium Excessive Agency · line 274 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
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 | $0.00075 | $0.10470 |
| Opus 5.5 | $0.00030 | $0.04188 |
| Sonnet 5.5 | $0.00015 | $0.02094 |
| Haiku 4.5 | $0.00007 | $0.01047 |
Grade A, and why
pre-landing-review 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 — 859 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Pre-Landing PR Review
You are running the specialized pre-landing workflow. Analyze the current branch's diff against the base branch for structural issues that tests don't catch. Do not present this skill as the product /review command.
OpenBitFun Dispatch
When this skill is invoked by OpenBitFun, this skill supplies the pre-landing review lens. Use existing Task sub-agents for independent diff review tracks, then consolidate findings in the main session.
- Do not assume a Staff Engineer sub-agent exists. Choose only from the Task tool's available agents.
- Use at most one built-in
CodeReviewsub-agent for an independent pass, and put the exact correctness, performance, security, or architecture question in its prompt. Broader dynamic lens selection belongs to the unified/reviewpath. - Prefer a matching custom review sub-agent when the user configured one. Use
Exploreonly for broad read-only investigation when no review sub-agent fits. - Keep Task work read-only. Ask for tight findings with file paths, line references if possible, severity, confidence, and why tests might miss it.
- The main session owns final severity ordering, AUTO-FIX vs ASK classification, and any code changes.
Step 1: Check branch
- Run
git branch --show-currentto get the current branch. - If on the base branch, output: "Nothing to review — you're on the base branch or have no changes against it." and stop.
- Run
git fetch origin <base> --quiet && git diff origin/<base> --statto check if there's a diff. If no diff, output the same message and stop.
Step 1.5: Scope Drift Detection
Before reviewing code quality, check: did they build what was requested — nothing more, nothing less?
- Read
TODOS.md(if it exists). Read PR description (gh pr view --json body --jq .body 2>/dev/null || true). Read commit messages (git log origin/<base>..HEAD --oneline). If no PR exists: rely on commit messages and TODOS.md for stated intent — this is the common case since /review runs before /ship creates the PR. - Identify the stated intent — what was this branch supposed to accomplish?
- Run
git diff origin/<base>...HEAD --statand compare the files changed against the stated intent.
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 Changed · +1 tokens per session a0939e64810a
- 1mo ago First seen · 859 lines · 74 tokens per session scan A 5466a4879991
pre-landing-review is a skill published in the GitHub repository GCWing/BitFun (2,077 stars, last pushed 1mo ago), licensed MIT. It adds 75 tokens to every session and 10,470 once invoked, about $0.0003 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 skills, from other repositories
memstack-development-code-reviewer
Use this skill when the user says 'review code', 'code review', 'check my code', 'audit this', 'review PR', 'review changes', 'what's wrong with this', or is requesting a structured review of code quality, security, performance, or maintainability. Do NOT use for refactoring plans or test generation.
shard
Use when the user says 'shard this', 'split file', or when working with files over 1000 lines.
task-management
Use before any Worker taskflow call or assigned-task workflow, including reading task state, acknowledging a task, executing a task, tracking progress, handling blockers/questions, submitting structured results, or reporting completion. Always use this skill when the message mentions assigned task, task ID…
task-coordination
Coordinate access to shared task directories using .processing marker files. Use before accessing a Worker's workspace to prevent conflicts when both Manager and Worker might modify files simultaneously.
mcporter
Discover and call MCP Server tools via the mcporter CLI. Use when your coordinator notifies you about new MCP tools, or when you need to call external APIs. Includes workflow for generating skill documentation for new MCP servers.
find-simplifications
Use for a periodic repo-wide sweep of qwen-code for accumulated excess surface — dead components and files, orphaned locale keys, exports nothing consumes, added-then-removed scaffolding — filing candidates on a tracking issue and landing only what a maintainer has said yes to. Repo-wide and evidence-first; every…