# Code Annotations > Code annotation requirements for pikru. Use when writing or porting Rust functions from C code. All ported functions must have cref comments. Use when this capability is needed. - Skill: `tomevault-io/code-annotations` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/code-annotations` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/code-annotations/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/code-annotations --- # Code Annotations All Rust functions ported from C must be annotated with a cref comment: ```rust // cref: c_function_name fn rust_function() { ... } ``` ## Purpose The `// cref:` comments create a traceable link between the Rust implementation and the original C function it was ported from. This helps: - Future maintainers understand the origin of the code - Cross-reference behavior between C and Rust implementations - Debug discrepancies between the two implementations --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/bearcove) — claim your Tome and manage your conversions.