Update instructions for local dev setup

Author: courtney-sims

apps/sandbox-container/.dev.vars.example

@@ -0,0 +1,2 @@
+CLOUDFLARE_CLIENT_ID=
+CLOUDFLARE_CLIENT_SECRET=

apps/sandbox-container/README.md

@@ -4,9 +4,17 @@ This is a simple MCP-based interface for a sandboxed development environment.
 
 ## Local dev
 
-Currently a work in progress. Cloudchamber local dev isn't implemented yet, so we are doing a bit of a hack to just run the server in your local environment.
+Cloudchamber local dev isn't implemented yet, so we are doing a bit of a hack to just run the server in your local environment. Because of this, testing the container(s) and container manager locally is not possible at this time.
 
-TODO: replace locally running server with the real docker container.
+Do the following from within the sandbox-container app:
+
+1. Copy the `.dev.vars.example` file to a new `.dev.vars` file.
+2. Get the Cloudflare client id and secret from a team member and add them to the `.dev.vars` file.
+3. Run `pnpm i` then `pnpm dev` to start the MCP server.
+4. Run `pnpx @modelcontextprotocol/inspector` to start the MCP inspector client.
+5. Open the inspector client in your browser and connect to the server via `http://localhost:8976/workers/sandbox/sse`.
+
+Note: Temporary files created through files tool calls are stored in the workdir folder of this app.
 
 ## Deploying