Header Only C Cpp Ingestion

Header-First C/C++ Ingestion (Interface Contract Protocol)

Overview

In systems programming codebases (C, C++, CUDA, Rust, Go), implementation files (.cpp, .c, .cu) are packed with thousands of lines of memory allocations (malloc, smart_ptr), low-level bitwise operations, cache alignments, and loop unrollings.

When an AI agent needs to integrate with a module or understand its public API, ingesting 2,000-line .cpp implementation files burns 15,000+ tokens on internal execution details.

The Header-First Ingestion Protocol directs the agent to inspect the lightweight interface header (.h, .hpp, .hxx) first. The header provides 100% of the class interfaces, struct layouts, enum constants, and method prototypes in 15% of the token cost.

Heavy .cpp Implementation vs. Lightweight .hpp Header

┌─────────────────────────────────────────────────────────────┐
│                 C/C++ Ingestion Economics                   │
│                                                             │
│  Full Implementation Ingestion (`engine.cpp` - 4,800 Tokens):│
│  • 1,200 lines of SIMD vectorization, cache tiling, locks   │
│  • Low-level memory buffers and mutex synchronization       │
│  ↳ 4,800 tokens billed, high cognitive noise                │
│                                                             │
│  Header Interface Ingestion (`engine.hpp` - 380 Tokens):    │
│  • Struct layout (`EngineConfig`, `FrameBuffer`)            │
│  • Class declaration (`RenderEngine`)                       │
│  • Method prototypes (`init()`, `renderFrame()`, `stop()`)  │
│  ↳ 380 clean tokens (92.1% Reduction!), 100% API clarity    │
└─────────────────────────────────────────────────────────────┘

The 2-Tier Inspection Hierarchy

┌───────────────────────────────────────────────────────────────────────────┐
│ TIER 1: INSPECT HEADER FIRST (`.h` / `.hpp` / `.d.ts` / `traits.rs`)      │
│ • Extract struct fields, class signatures, and public methods             │
│ • Formulate complete integration plan or caller code                      │
│                                                                           │
│ TIER 2: SLICE IMPLEMENTATION ONLY IF FIXING A BUG (`.cpp` / `.c`)        │
│ • If modifying an internal method: use line-bounded `view_file`           │
│   (e.g., lines 140-180 of `engine.cpp` rather than the entire 1,200 lines)│
└───────────────────────────────────────────────────────────────────────────┘

Multi-Language Interface-First Equivalents

The Header-First philosophy applies across compiled and strongly-typed ecosystems:

Concrete Agent Workflow Example

When asked: "Add a Prometheus metric counter to the C++ connection pool."

Step 1 (Header-First Protocol):

{
  "AbsolutePath": "include/net/connection_pool.hpp",
  "toolAction": "Inspecting connection pool header",
  "toolSummary": "Reading C++ Header Interface"
}

Agent identifies method prototype: void recordConnection(const Connection& conn); at line 45.

Step 2 (Targeted Implementation Slice):

{
  "AbsolutePath": "src/net/connection_pool.cpp",
  "StartLine": 120,
  "EndLine": 155,
  "toolAction": "Viewing recordConnection method body",
  "toolSummary": "Reading Targeted C++ Slice"
}

Benchmark Comparison

Navigating and integrating with a 15-module C++ networking engine:

Agent Operational Directive

MANDATORY: When analyzing native C/C++ or strongly typed codebases, agents MUST read .h/.hpp header files first. Open the corresponding .cpp implementation file only if actively modifying an internal method, and always use line-bounded slices (StartLine/EndLine).