`wrap()` — Generic Object Wrapper

wrap() is Rastir’s universal instrumentation function. It wraps any Python object so its public methods emit Rastir spans — useful for infrastructure components (Redis, databases, vector stores) and MCP sessions.

Basic Usage

import rastir

# Wrap a Redis client — all public methods emit INFRA spans
cache = rastir.wrap(redis_client, name="redis")
cache.get("key")       # → span: "redis.get"
cache.set("key", val)  # → span: "redis.set"

# Wrap a database client with filtering
db = rastir.wrap(db_client, name="postgres",
                 include=["query", "execute"],
                 span_type="tool")

Smart MCP Detection

wrap() auto-detects MCP ClientSession objects and delegates to the MCP-specific proxy that intercepts call_tool() and injects distributed trace context.

from rastir import wrap

# These are equivalent:
session = wrap(mcp_session)           # auto-detects MCP session
session = wrap_mcp(mcp_session)       # explicit (still works)

# After wrapping, call_tool() injects trace IDs automatically:
await session.call_tool("search", {"query": "hello"})
# → client span with remote="true", trace context injected

wrap_mcp() remains available as an explicit alias for backward compatibility.

API Reference

wrap(
    obj,
    *,
    name: str = None,        # Span name prefix (default: class name)
    span_type: str = "infra", # infra, tool, llm, trace, agent, retrieval
    include: list[str] = None,# Only wrap these methods
    exclude: list[str] = None,# Skip these methods
)

For MCP sessions: name, span_type, include, and exclude are ignored — the MCP proxy handles its own span creation.

Features

Feature	Description
Sync + async	Both sync and async methods are wrapped automatically
`isinstance` preserved	`isinstance(wrapped, OriginalClass)` returns `True`
Double-wrap prevention	Objects with `_rastir_wrapped` are returned as-is
Method caching	Wrapped methods are cached — no overhead on repeated access
Private methods skipped	Methods starting with `_` are not wrapped
MCP auto-detection	Detects `ClientSession` from MCP SDK and delegates to MCP proxy

Span Attributes

Each wrapped method call produces a span with:

Attribute	Value
`wrap.method`	Method name (e.g., `get`, `set`)
`wrap.args_count`	Number of positional arguments
`wrap.kwargs_keys`	Sorted list of keyword argument names

Usage in Frameworks

Framework	Usage
LangGraph	Not needed — `@langgraph_agent` auto-discovers LLMs/tools
CrewAI	Not needed \u2014 `@crew_kickoff` auto-wraps LLMs/tools; MCP handled natively by CrewAI
LlamaIndex	`wrap(llm, span_type="llm")` and `wrap(tool, span_type="tool")`
Infrastructure	`wrap(redis_client, name="redis")` for any object

Valid Span Types

Type	Use for
`infra` (default)	Databases, caches, HTTP clients
`tool`	Tool invocations
`llm`	LLM calls
`trace`	General tracing
`agent`	Agent-level operations
`retrieval`	RAG retrieval operations

wrap() — Generic Object Wrapper