New Feature Announcement

/config

Live Session Configuration for Amplifier

Modify your running session without restarting.
Disable tools, toggle behaviors, tune config — all live.

Active April 2026

The Problem

Configuration means restarting

🛑

Stop what you're doing

You're mid-task and a tool keeps firing that you don't need. Or a context file is confusing the LLM. You have to exit your entire session to change it.

📝

Edit YAML manually

Open settings.yaml, find the right key, figure out the syntax for overrides, hope you don't break the indentation. Then save.

🔄

Restart and rebuild

Session restarts. Your context reloads. Your mental model resets. You lose your flow — all because you needed one toggle.

The Solution

Modify everything mid-session

New /config commands give you full control over your running session — no restart required.

# See all available commands
/config

# Full live dashboard of your session
/config show

# Disable a noisy tool or irrelevant context
/config tools disable bash
/config context disable coding-standards.md
/config behaviors disable code-review

# See what you've changed
/config diff

# Save preferences for next session
/config save

The Dashboard

/config show — your session at a glance

Every tool, hook, context file, agent, provider, and behavior — with live status, config values, and which behavior contributed each item.

🔧 Tools

● bash ← core-tools

● read_file ← core-tools

● web_search ← research (disabled)

● LSP ← coding

📎 Context

● coding-standards.md

● review-checklist.md (disabled)

🤖 Agents

● code-intel ← coding

● explorer ← core

🎭 Behaviors

● core-tools 6 tools, 2 context

● coding 3 tools, 1 agent

● research 2 tools (disabled)

⚡ Providers

● anthropic model: claude-…

Intelligent Design

Smart shared ownership

If two behaviors both contribute the same tool, disabling one won't break the other. The system tracks provenance — which behavior contributed each item — and only removes items exclusively owned by the disabled behavior.

Example: Both behaviors claim bash

core-tools

→

bash

read_file

write_file

devops ✕

→

bash ✓ safe

kubectl ✕ removed

Disabling devops removes kubectl (exclusive to devops) but keeps bash (still claimed by core-tools).

Persistence

Save once, apply forever

Your runtime tweaks don't have to be temporary. /config save writes your preferences to settings.yaml. Next session starts with your customizations applied automatically.

1

Tweak live

Disable tools, toggle behaviors, set config values during your session

2

Save

/config save writes disabled items and config overrides to settings.yaml

3

Auto-apply

Next session reads settings.yaml and applies your saved preferences on startup

4

Iterate

Re-enable anything anytime. Your config evolves with you.

Under the Hood

Clean architecture, zero core changes

The entire feature is additive — a new library in amplifier-foundation and a new renderer in amplifier-app-cli. No existing APIs were modified.

BundleStateManager

All mutation operations: disable/enable tools, providers, agents, contexts, behaviors. Stash safety for re-enabling. Shared ownership awareness.

821 lines

BundleInspector

All query operations: list methods for dashboard, namespace resolution, module-to-tool mappings, snapshot and diff.

479 lines

SessionConfigurator

Public facade that delegates to StateManager and Inspector. Clean API surface for CLI consumption.

231 lines

DashboardRenderer

Rich-formatted terminal UI. Color-coded status, config value trees, behavior provenance annotations, secret redaction.

447 lines

configuration:changed

Event emitted on every toggle so modules can react (e.g., skills tool unloads when disabled)

333 tests

220 foundation + 113 CLI (per PR descriptions; includes configurator, provenance, and regression suites)

~2,370 lines

Production code across both repos (1,920 foundation configurator + 447 dashboard renderer)

Development Velocity

Built in a weekend

2

Repos

58

Commits

2

PRs merged

~2

Days of dev

Timeline: April 14 (first commit) → April 15 (last commit) → April 16 (PRs merged)

Primary contributor: Brian Krabach (sole author, 100% of commits)

amplifier-foundation#160 amplifier-app-cli#158

Sources

Research Methodology

Data as of: April 16, 2026

Feature status: Active (both PRs merged)

Research performed:

Git log analysis: git log --all --grep="configurator|BundleState|BundleInspector" --no-merges — 35 commits in foundation
Git log analysis: git log --all --grep="config|configurator|dashboard" --no-merges — 27 /config-specific commits in app-cli
PR metadata: gh pr view 160 --json title,body,author,mergedAt,additions,deletions,state (amplifier-foundation)
PR metadata: gh pr view 158 --json title,body,author,mergedAt,additions,deletions,state (amplifier-app-cli)
Line counts: wc -l on configurator/, _provenance.py, dashboard_renderer.py
Test counts: grep -c "def test_" on test files (130 + 20 + 89 = 239 test functions; PR descriptions report 220 + 113 = 333 including parametrized expansions)
Contributors: git log --format="%an" --all --grep="configurator" — sole contributor: Brian Krabach

Repos: microsoft/amplifier-foundation, microsoft/amplifier-app-cli

Gaps: Addition/deletion counts from PRs include lock files (166K and 105K respectively) which inflate raw line counts. Production code line counts derived from direct wc -l on source files. Test count discrepancy (239 functions vs 333 PR-reported) likely due to parametrized test expansion.

Known limitations from PR: Hook toggle is read-only (core suspend/resume API needed). Tool module mapping uses heuristics. Shared ownership uses last-writer-wins provenance.

Try It Now

Available on main

Update Amplifier and type /config in any session.

⚡

/config show

See everything in your session

🎛️

/config tools disable

Toggle tools, contexts, behaviors

💾

/config save

Persist for every future session

amplifier-foundation#160 + amplifier-app-cli#158

Both merged April 16, 2026