Pattern 14: Knowledge Retrieval (Search / RAG Hooks)¶

"Route retrieval requests to external search and merge results into context"

Codex surfaces web search calls as explicit tool items and tracks begin/end via synthetic events.

Codex references: - codex-rs/core/src/client.rs (detect web_search_call, emit WebSearchCallBegin) - codex-rs/core/src/codex.rs (handle begin/end events)

Example (Python)¶

class Retriever:
    def search(self, query: str) -> list[str]:
        return [f"Result for {query}"]

def answer_with_retrieval(q: str, retriever: Retriever) -> str:
    hits = retriever.search(q)
    return f"Q: {q}\nSources: {hits}"