page:recipes:mcp server:express:artifact storage

Host mcp server with Express: stored input and output artifacts

Summary

Deploy a mcp server built with Express on Ample using the generated downloads pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Express: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the mcp server-specific behavior as your application code.

Representative Queries

Resource Requirements

Infrastructure Requirements

  1. Compute
    • Status: verified
    • Summary: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
  2. Postgres
    • Status: verified
    • Summary: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
  3. S3-compatible object storage
    • Status: verified
    • Summary: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

Framework

Express

Workload

MCP server

Release Status

published

Support Status

verified

Execution Status

ready

Prerequisites

Tested Configuration

Input Schema

{  
  "additionalProperties": false,  
  "properties": {  
    "env": {  
      "description": "Encrypted environment variables (bucket credentials, secrets)",  
      "items": {  
        "pattern": "^[A-Z][A-Z0-9_]*=.*$",  
        "type": "string"  
      },  
      "maxItems": 50,  
      "type": "array"  
    },  
    "name": {  
      "description": "App name",  
      "maxLength": 63,  
      "minLength": 1,  
      "pattern": "^[a-z0-9-]+$",  
      "type": "string"  
    },  
    "path": {  
      "description": "Project directory or ample.toml service",  
      "maxLength": 512,  
      "minLength": 1,  
      "type": "string"  
    },  
    "release_command": {  
      "description": "Migration command run before activation",  
      "maxLength": 512,  
      "type": "string"  
    }  
  },  
  "required": [  
    "env",  
    "name",  
    "path"  
  ],  
  "type": "object"  
}

Workflow Steps

  1. Build and start
    • Command: npm install, npm run build --if-present, npm run start on the node-22 template. The server must bind 0.0.0.0 on PORT.
  2. Implement the pattern on PostgreSQL
    • Create a fixture’s module that implements generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Keep migrations idempotent and run them with --release-command.
  3. Wire object storage
    • Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
  4. Deploy
    • Command: ample deploy . --name --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
  5. Verify
    • Command: ample logs --kind build

Examples

Success Checks

  1. App responds on its public URL
    • Kind: http_get
    • Path: /
    • Expect: ample canary express patterns
  2. Generated-downloads self-test
    • Kind: http_get
    • Path: /p/generated-downloads
    • Expect: export=ok rows=3 (with ?token=...; 401 without)

Limitations

Cost Estimate

Evidence Summary

  1. Canary run: Express pattern fixture deployed on Ample; checks passed for generated-downloads and configuration-secrets.
    • Observed At: 2026-09-21T02:34:39Z
  2. Canary run: The same Express app deployed with a --release-command migration; the marker it created was readable after activation.
    • Observed At: 2026-09-20T01:54:51Z

Next Actions

  1. Browse the catalog index
    • Operation ID: catalog_index
    • Method: GET
    • Relative Path: /v1/catalog
  2. Search published recipes by intent, stack and constraints
    • Operation ID: search_recipes
    • Method: POST
    • Relative Path: /v1/catalog/search
    • Parameters: {"body":{"limit":5,"query":"Host mcp server with Express: stored input and output artifacts"}}
  3. Prepare a side-effect-free deployment plan for an authorized project
    • Operation ID: plan_deployment
    • Method: POST
    • Relative Path: /v1/catalog/plan
    • Parameters: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:mcp-server:express:artifact-storage","recipeRevision":"r1"}}
  4. Read the existing agent authentication setup
    • Operation ID: existing_auth_setup
    • Method: GET
    • Relative Path: /mcp/setup
  5. Browse MCP server
    • Operation ID: browse_node
    • Method: GET
    • Relative Path: /v1/catalog/nodes/workload%3Amcp-server
  6. Browse Express
    • Operation ID: browse_node
    • Method: GET
    • Relative Path: /v1/catalog/nodes/stack%3Aframework-express
  7. Browse Generated downloads
    • Operation ID: browse_node
    • Method: GET
    • Relative Path: /v1/catalog/nodes/pattern%3Agenerated-downloads
  8. Browse Deploy MCP server
    • Operation ID: browse_node
    • Method: GET
    • Relative Path: /v1/catalog/nodes/intent%3Adeploy-mcp-server