updated readme

ISSUE: CLDSRVCLT-1

Author: SylvainSenechal

README.md

@@ -1,2 +1,26 @@
 # cloudserverclient
-Client for custom cloudserver routes
+
+This directory contains the Smithy-based TypeScript/JavaScript client for Cloudserver's custom internal APIs. The client is generated from the .smithy model files that we defined in the /models folder.
+
+If you need to work on it, install Smithy first : https://smithy.io/2.0/guides/smithy-cli/cli_installation.html
+
+## Architecture
+
+Each .smithy file defines one api, and we have the Cloudserver service defined in models/cloudserver.smithy uses these apis.
+
+The client generation is performed this way :
+
+```bash
+# Generate TypeScript from .smithy model files
+yarn run generate-smithy-client
+
+# Compile TypeScript to JavaScript and create npm package
+yarn run build-smithy-client
+```
+
+### Local testing
+
+1. Install test dependencies: `cd localTests && bun install`
+2. Start CloudServer: `S3VAULT=mem S3METADATA=mem S3DATA=mem REMOTE_MANAGEMENT_DISABLE=true yarn start`
+3. Initialize test data: `bun initBucketForTests.ts`
+4. Run tests: `bun testsApis.ts` (or other test files)