Distinguish the two JSON documents first

1. Read structured user input

The following example shows business fields that are safe to display. It illustrates the file structure; it is not a request body for users to write. The real file is generated by the platform and also contains platform fields for the runtime contract.

{
  "schema_version": "oasn.invocation.v1",
  "invocation_id": "inv-example",
  "run_id": "run-example",
  "input": {
    "user_prompt": "Read the attachment and generate an interactive sales dashboard",
    "args": [],
    "attachments": [
      "/oasn/in/files/file-sales-csv"
    ]
  }
}

Read the file only when the business logic truly needs the raw structure; ordinary OpenClaw Skills and Plugins normally receive the message directly. When parsing is required, keep the server-side read minimal:

from json import loads
from pathlib import Path

payload = loads(Path("/oasn/in/invocation.json").read_text(encoding="utf-8"))
business_input = payload.get("input", {})
user_prompt = business_input.get("user_prompt", "")
attachments = business_input.get("attachments", [])

if not isinstance(user_prompt, str) or not isinstance(attachments, list):
    raise ValueError("INVALID_INVOCATION_INPUT")

2. Declare business ports with CLI 0.7.3

The website's Version form does not currently have WebUI-port controls. Configure ports through the Skill-verified oasn-sa-dev CLI. First confirm version 0.7.3 or later, then query the complete current list:

oasn-sa-dev --version
oasn-sa-dev version webui-ports get --version-id <agent_version_id>

After the developer explicitly confirms the complete list of ports to expose, run set. It replaces the entire list; it does not append:

# Replace the complete list with 7860 and 8765
oasn-sa-dev version webui-ports set --version-id <agent_version_id> --ports 7860,8765

# Clear the list only when all WebUIs are explicitly being disabled
oasn-sa-dev version webui-ports set --version-id <agent_version_id> --clear

• Each port must be a unique integer in 1..65535 and must not use platform-reserved ports 22, 18789, or 18790.
• When there is no active Workspace, the Version declaration is only saved. When there is an active Workspace, the mapping is updated in place without rebuilding the Sandbox.
• sync_status=ready proves only that declaration synchronization completed. Also confirm proxy_status=ready; only then should you deliver the current webui_urls.
• A ready proxy is still not proof of business health. Visit the page and API for real; if WebSocket is used, also verify message round trips and reconnection.
• Setting the same ports again is an idempotent no-op and does not refresh links that have already become invalid.

To keep all ports and create a new generation of business links, first run get, obtain explicit authorization to refresh, and then run:

oasn-sa-dev version webui-ports refresh --version-id <agent_version_id>

How to interpret port status

3. Implement a service that works under the proxy subpath

1. Listen on all container interfaces

   The business process must listen on 0.0.0.0:<declared-port>, not only on localhost. The CLI only establishes the mapping; it does not start or stop the process or prove that it is healthy.

2. Provide a business page and a minimal health endpoint

   At minimum, make the target page and business API return verifiable content. The Program determines how it starts the process; the current contract does not require a fixed start-webui.sh or a fixed health path.

3. Preserve the proxy prefix

   The WebUI is mounted under a /webui/proxy/<id>/ subpath. fetch('/api/health') and src="/vendor/app.js" discard that prefix. The page, SPA routes, static assets, and WebSocket should all resolve their base from the current URL.

const prefix = window.location.pathname.match(/^.*\/webui\/proxy\/[^/]+\//)?.[0]
const base = prefix
  ? new URL(prefix, window.location.origin)
  : new URL('./', window.location.href)

fetch(new URL('api/health', base))
const scriptUrl = new URL('vendor/app.js', base)

Do not hard-code a Sandbox IP, 127.0.0.1, a development Workspace's public URL, or an external domain in page code. Note that the internal WebUI declaration in the next section must use a loopback URL; that does not conflict with the relative-address rule inside browser pages.

4. The final reply must contain strict oasn-webui JSON

After the page is running and reachable, make the final Assistant reply from main include ordinary explanatory text and one lowercase fenced block per page:

The dashboard is ready. Open it to view the results.

```oasn-webui
{"type":"webui","title":"Sales dashboard","url":"http://127.0.0.1:7860/results?range=q3#summary","defaultOpen":true}
```

• The JSON must be an object containing exactly these four fields. Do not add token, description, or custom fields.
• The fence info must be exactly lowercase oasn-webui. Do not use an ordinary json block or append parameters to the fence info.
• The port must be declared on the Version. Do not copy a public webui_urls value returned by the CLI into the block.
• Internal HTTP allows only 127.0.0.1 or localhost. An external page must use safe public HTTPS; public HTTP and private-network addresses are not allowed.
• The URL must not contain a username or password, and its query or fragment must not carry sensitive state such as token, secret, signature, credential, password, authorization, or api_key.
• You may provide multiple blocks for multiple pages. The current parser preserves multiple defaultOpen=true values, but the interaction contract allows at most one page to be true so that clients do not open several pages in succession. This is a developer rule; do not mistake it for server-side rejection.

Three common mistakes

# Wrong: defaultOpen is a string
{"type":"webui","title":"Dashboard","url":"http://127.0.0.1:7860/","defaultOpen":"true"}

# Wrong: the URL is relative and there is an extra custom field
{"type":"webui","title":"Dashboard","url":"/results","defaultOpen":true,"token":"..."}

# Wrong: the platform output field uri is used as a developer input field
{"type":"webui","title":"Dashboard","uri":"https://example.invalid/","defaultOpen":true}

A block with invalid JSON syntax, missing fields, or incorrect types does not become a WebUI view and normally remains verbatim in the text. If the structure is valid but the URL uses an undeclared port, a private-network address, or sensitive state, production projection closes with OPENCLAW_FINAL_REPLY_INVALID. If later result-layer validation fails again, it returns RUN_RESULT_INVALID or MCP_INVOCATION_RESULT_INVALID; it does not hide the error behind partial success.

5. url becomes uri in platform output

The developer is responsible only for the final reply in the previous section and does not construct the following object directly. After the platform validates and proxies the page, the client reads trusted structuredContent.views[], where the field is named uri:

{
  "content": [
    {"type": "text", "text": "The dashboard is ready. Open it to view the results."}
  ],
  "structuredContent": {
    "view": "invocation_result",
    "status": "completed",
    "invocation_id": "inv-example",
    "views": [
      {
        "type": "webui",
        "uri": "https://platform-controlled-host/webui/proxy/.../results?range=q3#summary",
        "title": "Sales dashboard",
        "defaultOpen": true
      }
    ]
  },
  "isError": false
}

Integration clients should trust structuredContent.views[] instead of reparsing the fence in the text. A view with defaultOpen=false should remain a visible entry point; it simply does not open automatically. Failure to open a browser page also must not rewrite the Agent's completed terminal state or automatically invoke the Agent again.

6. Accept at four layers, not just by seeing HTTP 200

1. Local Sandbox service

   Confirm that the process listens on 0.0.0.0, access the target page and API through loopback, and verify the business response content.

2. Port and proxy status

   Run version webui-ports get and confirm ports, sync_status=ready, proxy_status=ready, and the current webui_urls together.

3. Development proxy page

   Open every new URL and verify the page, nested routes, static assets, and API. If WebSocket is used, verify round trips and reconnection. A 410 means that the business proxy session is invalid; it does not mean Owner OAuth is invalid. For a 502, check the business listener first.

4. Final result and production invocation

   Have the Agent return a real block, confirm that it is projected as a view/canvas, and verify that the path, query, and fragment are preserved without sensitive state. After publishing, run one more production invocation; development WebChat is not a substitute.

Pre-publish I/O gates

• A normal request returns non-empty, useful final text consistent with the input.
• Structured input reads only input.user_prompt and the current input.attachments; it does not expose the complete file.
• A file output can be downloaded and its contents verified; a local path alone is not sufficient.
• The port declaration is frozen, both sync_status and proxy_status are ready, and every page has been tested for real.
• Every WebUI block has exactly four fields, uses the matching port, and contains no sensitive URL state; the client receives a trusted views[].uri.
• Missing input, unsupported formats, an invalid proxy, or capability failure returns a stable, actionable error.