Delegate Tool Feature

Context Inheritance

Smarter agent delegation through two-parameter context control

Active

February 2026

The Problem

Child Agents Start from Zero

🧠

Parent Agent

Has full conversation history — knows what the user asked, what was discussed, and what decisions were made

❓

Child Agent

Starts with a blank slate — receives only the instruction string, with no surrounding conversation context

Every delegation required manually re-explaining the conversation in the instruction string

The Fix

Before & After

Before — Verbose

delegate(
  agent="explorer",
  instruction="""Find auth bug.
    User reports 401 errors after login.
    We discussed session token handling.
    They tried clearing cookies.
    Using the React frontend..."""
)

After — Automatic

delegate(
  agent="explorer",
  instruction="Find auth bug"
)
# Smart defaults handle the rest:
#   context_depth="recent"
#   context_scope="conversation"
#   context_turns=5

Child automatically receives the last 5 conversation turns — no manual re-explanation needed

The Design

Two Independent Parameters

context_depth — How Much

none	Clean slate — no parent context passed
recent	Last N turns (default: 5). Most common choice.
all	Full conversation history

context_scope — Which Content

conversation	User/assistant text only — no tool calls leak
agents	+ delegate results included
full	+ all tool results included

Mix and match: recent depth with agents scope gives recent context including prior delegate results

Architecture

How It Works

Parent Agent

→

Delegate Tool

→

Child Agent

↓

Reads context_depth and context_scope from call parameters
Extracts messages from parent’s ContextManager
Filters by scope (conversation / agents / full)
Trims by depth (none / recent N / all)
Passes filtered context to child session

Module-level implementation — uses existing ContextManager API, no kernel changes required

Philosophy

Design Principles

01

Smart Defaults

Default recent with 5 turns means context flows automatically without extra configuration

02

Two Orthogonal Axes

Separate “how much” from “which content” — independent controls for precise context shaping

03

Turn-Based Counting

Count exchanges, not messages — “last 3 turns” is more intuitive than “last 6 messages”

04

Safety Caps

Bundle-level max_turns config (default: 10) prevents runaway context from overwhelming child agents

Development

Velocity

1

Repository

~35

Commits

1,109

Lines of code

2

Days to production

PR #44 merged January 30, 2026 → promoted to production February 1, 2026

Primary contributor: Brian Krabach (~97% of delegate-related commits)

Sources

Research Methodology

Data as of: February 20, 2026

Feature status: Active (in production bundle via behaviors/agents.yaml)

Repository: microsoft/amplifier-foundation

Research performed:

Git log analysis: git log --all --oneline --grep="delegate" (~35 commits found)
PR review: git show b73813b --stat (PR #44: 11 files, +1,718/−95 lines)
Source inspection: wc -l modules/tool-delegate/__init__.py (1,109 lines)
Parameter verification: grep -n "context_depth\|context_scope" __init__.py
Contributors: git log --format="%an" --grep="delegate" (Brian Krabach: 34/35 commits)
Feature status: grep "tool-delegate" behaviors/agents.yaml (confirmed active in bundle)
Core session check: grep -n "context\|parent" amplifier_core/session.py (ContextManager API)

Gaps: No instruction-length reduction metrics measured. No performance benchmarks available. Impact of shorter delegation calls is qualitative, not quantified.

Primary contributor: Brian Krabach (~97% of delegate-related commits)

Try It

Delegate Smarter

Context flows automatically. Just delegate.

delegate(
  agent="foundation:explorer",
  instruction="Find the auth bug",
  context_depth="recent",
  context_scope="agents"
)

microsoft/amplifier-foundation