feat(sandbox): stop generating client-side default names so unnamed creations can use warm pools (ENG-3931)

[devin-ai-integration]

Summary

Warm sandbox pools (ENG-3889) only serve creations where metadata.name is absent. But SandboxInstance.create / SyncSandboxInstance.create generated a client-side default name (sandbox-<8 hex>) whenever the caller omitted one, so every unnamed SDK creation reached the API with a name and silently fell back to the slow classic path.

This drops the client-side default name. When the caller doesn't provide a name we now send the create request without metadata.name and let the server assign one; the server-assigned name is surfaced on the returned instance as before.

Because the generated Metadata.to_dict() always emits name, a small helper serializes the body and strips the key when unnamed:

def _create_body(sandbox: Sandbox) -> Union[Sandbox, Dict[str, Any]]:
    if sandbox.metadata and sandbox.metadata.name:
        return sandbox            # named → send the model as-is
    body = sandbox.to_dict()
    body["metadata"].pop("name", None)   # unnamed → omit metadata.name
    return body

create_sandbox's generated client already accepts a dict body, so no generated code changes. The same change is applied to both the async (default/) and sync (sync/) implementations.

Notes:

• Explicitly named creations are unchanged.
• create_if_not_exists still requires a name (unchanged) — it needs one for its existence check.

Test

Added unit tests in tests/core/test_sandbox.py (async + sync) asserting the create body omits metadata.name for unnamed / raw-model creations, keeps a caller-provided name, and surfaces the server-assigned name.

Same change made in the TypeScript SDK: blaxel-ai/sdk-typescript#(companion PR).

Link to Devin session: https://app.devin.ai/sessions/652893c91fb340faa3d0064943629994
Requested by: @cploujoux

---

Note

Removes client-side default name generation (sandbox-<hex>) from SandboxInstance.create and SyncSandboxInstance.create, so that unnamed sandbox creations reach the API without metadata.name and can be served by warm sandbox pools. A _create_body helper strips the name key from the serialized dict when no name was provided.

^{Written by Mendral for commit a764b9c.}

[devin-ai-integration]

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[mendral-app]

🧪 Testing Guide

What this PR addresses

The SDK was generating a client-side default name (sandbox-<8 hex>) whenever a caller created a sandbox without specifying a name. This caused every unnamed creation to hit the API with a metadata.name, making it ineligible for warm sandbox pools (which only serve requests where metadata.name is absent). This PR removes the client-side default so unnamed creations reach the API without a name, enabling the server to assign one and route the request through the warm pool path.

Steps to reproduce the original issue

1. Call SandboxInstance.create({"image": "blaxel/base-image:latest"}) (or the sync equivalent) without providing a name field.
2. Inspect the request body sent to the create_sandbox API (e.g., via mock or network trace).
3. Before this PR: metadata.name is always present (e.g., "sandbox-a1b2c3d4"), so the request bypasses warm pools.
4. After this PR: metadata.name is absent from the request body, allowing the server to assign a name and serve from a warm pool.

What to verify (expected behavior)

• Unnamed creation (dict config): When creating a sandbox via dict without a name key, the body sent to the API must be a dict with metadata.name not present (not None, not empty — the key itself should be absent).
• Named creation: When a name is explicitly provided (e.g., {"name": "mysbx", ...}), the body must include metadata.name == "mysbx" as before.
• Raw Sandbox model without metadata: Passing Sandbox(metadata=None, spec=SandboxSpec()) should also result in no metadata.name in the request body.
• Server-assigned name surfaced: The returned SandboxInstance should reflect the server-assigned name (from the API response), not a client-generated one.
• Sync path: All the above behaviors should be identical for SyncSandboxInstance.create.
• Existing tests pass: Run pytest tests/core/test_sandbox.py — the 6 new tests covering these scenarios should all pass, along with all pre-existing tests.

Note

Posted by PR Testing Guide · Tag @mendral-app with feedback.

[mendral-app]

✅ Linked to Linear issue ENG-3931 — status: In Review

The PR is now attached to the issue and will auto-close it when merged.

Note

Posted by Linear Issue Enforcer · Tag @mendral-app with feedback.