The Kernel in the IDE

Amplifier's full agent, native in VS Code

The Frame

Developers won't leave VS Code — so Amplifier's kernel moved into the editor

The amplifier-app-vscode extension — "VS Code extension for Amplifier AI agent framework" — brings AI assistance to where developers already work, instead of asking them to leave the editor for it.

And this isn't a concept — it already exists as shipped code.

Proof — It Already Exists

A shipped two-tier codebase, not a concept

Top-level, the repo splits into a TypeScript extension/ and a Python server/ — sibling tiers, real built code.

But shipping two tiers means bridging two very different runtimes.

3,128

lines of TypeScript in extension/src

2,102

lines of Python in server/

59

files in the initial commit (24,060 insertions)

0.1.0

version, published under the microsoft publisher

The Tension

Two runtimes that can't natively talk

Amplifier's kernel, amplifier-core, is Python and async. A VS Code extension must be TypeScript. The full agent framework lives on one side of a language wall — and the editor lives on the other.

So how do you get the real kernel across that wall?

Mechanism — Launch

The extension spawns the Python server, then waits for /health

One runtime launches the other: the TypeScript extension starts the Python backend as a child process and won't use it until it answers healthy.

Once it's up, what actually runs inside that server?

// ServerManager.ts — spawn via uv
cp.spawn('uv', ['run','python','-m',
  'amplifier_vscode_server'], {
  env: { AMPLIFIER_HOST, AMPLIFIER_PORT }
})

// waitForReady — 10s timeout
fetch(`${baseUrl}/health`)
  // poll until response.ok

Mechanism — The Real Kernel

It imports the real AmplifierSession — not a reimplementation

The server's session runner imports amplifier-core directly and runs the full kernel in-process: providers, tools, hooks, orchestrators, profiles.

But running the kernel is only half the job — its events have to reach the IDE.

# session_runner.py
from amplifier_core import AmplifierSession
from amplifier_profiles import (
  ProfileLoader, compile_profile_to_mount_plan)
from amplifier_collections import CollectionResolver
from amplifier_module_resolution import (
  StandardModuleSourceResolver)

The Turn

A 278-line bridge forwards the kernel's own events — pure forwarding

A streaming-bridge hook forwards amplifier-core's native events over HTTP + SSE — "pure event forwarding, no business logic." The gap between runtimes closes.

Which lands the whole point: the full kernel, live in the editor.

content_block:delta

Streamed model output, dispatched by the extension's EventStream

tool:pre

Tool call about to run — the same hook that gates approvals

thinking:delta

Model reasoning stream, forwarded through the SSE channel

The Payoff

The complete kernel runs live in VS Code — secure by default

Not a reimplementation — the real Amplifier, in the editor. Locked to localhost, behind a pinned CSP and a TOOL_PRE approval gate surfaced as an inline VS Code UI.

A pattern worth keeping beyond this one extension.

Bound to 127.0.0.1:8765

The backend binds to localhost by default

Pinned CSP + crypto nonce

connect-src pinned to the local server; per-render crypto.randomBytes(16) nonce

TOOL_PRE approval gate

Sensitive tool calls route to an inline approval UI with session-scoped always-allow

The Takeaway

Spawn the real engine locally, forward its native events

The reusable pattern: don't reimplement a Python engine in TypeScript — run the real one as a local child process and stream its own events into the editor over HTTP + SSE. The IDE gets the full thing, secure by default.

Experimental exploration project — no support provided

Sources

Research Methodology

Primary source: marklicata/amplifier-app-vscode (cloned to /tmp/amplifier-app-vscode), cross-referenced against amplifier-core (upstream microsoft/amplifier-core). Repo createdAt 2026-01-16; origin/main commits span 2025-12-15 to 2025-12-17.

Feature status: Experimental exploration project (README: "no support provided"); ROADMAP in Planning Phase.

Commands run:

gh repo view marklicata/amplifier-app-vscode --json name,description,createdAt,updatedAt,url
find extension/src -name '*.ts' | xargs wc -l | tail -1 → 3128 total; find server -name '*.py' | xargs wc -l | tail -1 → 2102 total
git show --stat e30fbdf | tail -1 → 59 files changed, 24060 insertions(+)
grep -n 'from amplifier' server/amplifier_vscode_server/core/session_runner.py
wc -l server/amplifier_vscode_server/hooks/streaming_bridge.py → 278
grep -n 'spawn|waitForReady|/health|AMPLIFIER_HOST|AMPLIFIER_PORT' extension/src/services/ServerManager.ts
grep -rn '127.0.0.1:8765' extension/src; grep -n 'Content-Security-Policy|connect-src|randomBytes' extension/src/providers/ChatViewProvider.ts
grep -n 'TOOL_PRE|request_approval' server/amplifier_vscode_server/hooks/approval_hook.py

Gaps: VS Code Marketplace publication described in README but not independently verified. Repo createdAt (2026-01-16) post-dates newest commit (2025-12-17); inferred as a repo publish/transfer date. amplifier-core cross-referenced from a local checkout — exact version parity with the pinned dependency not verified.

Primary contributor: Samuel Lee — all 7 commits on origin/main.