FFI Design
Expert skill for designing and implementing foreign function interfaces to native code
npx skills add a5c-ai/babysitter --skill ffi-design --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# FFI Design Skill ## Overview Expert skill for designing and implementing foreign function interfaces to native code. ## Capabilities - Design FFI declaration syntax - Implement type marshaling between languages - Handle C calling conventions (cdecl, stdcall, fastcall) - Implement callback support (native calling managed) - Handle string encoding conversions - Implement struct layout matching (padding, alignment) - Design memory ownership transfer rules - Support dynamic library loading ## Target Processes - ffi-implementation.js - interpreter-implementation.js - bytecode-vm-implementation.js - code-generation-llvm.js ## Dependencies - libffi - Platform ABI documentation ## Usage Guidelines 1. **Safety**: Design safe wrappers around unsafe FFI calls 2. **Marshaling**: Document type marshaling rules explicitly 3. **Ownership**: Make memory ownership clear at FFI boundaries 4. **Callbacks**: Handle callback lifetimes carefully 5. **Strings**: Handle string encoding conversions correctly (UTF-8, UTF-16) ## Output Schema ```json { "type": "object", "properties": { "callingConventions": { "type": "array", "items": { "type": "string" } }, "marshalingRules": { "type": "array", "items": {
- Overview
- Capabilities
- Target Processes
- Dependencies
- Usage Guidelines
- Output Schema
What does the FFI Design skill do?
Expert skill for designing and implementing foreign function interfaces to native code
How do I install it?
Run `npx skills add a5c-ai/babysitter --skill ffi-design --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From a5c-ai/babysitter, a repository with 1,642 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.