GET /v1/vector_stores crashes with AttributeError once last_active_at is set

[SecMyth]

⚠️ Note: This issue was drafted with AI assistance. Please verify the analysis and reproduction steps before acting on it.

Description

GET /v1/vector_stores returns a 500 Internal Server Error as soon as any vector store has a non-null last_active_at (i.e., after at least one embedding has been added to it).

Error

Traceback (most recent call last):
  File "/app/main.py", line 187, in list_vector_stores
    last_active_at = int(row["last_active_at"].timestamp()) if row.get("last_active_at") else None
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'timestamp'

Root cause

main.py calls .timestamp() directly on the expires_at and last_active_at values returned by db.query_raw(), assuming Prisma's query_raw() returns datetime objects for timestamp columns. In practice it returns ISO-8601 strings for these fields, so the .timestamp() call fails. This affects both:

• create_vector_store (lines ~111–112)
• list_vector_stores (lines ~186–187)

Notably, created_at doesn't hit this bug because it's computed as an epoch value directly in SQL via EXTRACT(EPOCH FROM created_at)::bigint, while expires_at/last_active_at are passed through as raw column values.

Steps to reproduce

1. POST /v1/vector_stores to create a store
2. POST /v1/vector_stores/{id}/embeddings to add at least one embedding (this sets last_active_at)
3. GET /v1/vector_stores → 500 error

Suggested fix

Add a type-safe helper that accepts both datetime and str, and use it in place of the direct .timestamp() calls:

from datetime import datetime

def to_epoch_seconds(value):
    if value is None:
        return None
    if isinstance(value, datetime):
        return int(value.timestamp())
    if isinstance(value, str):
        return int(datetime.fromisoformat(value.replace("Z", "+00:00")).timestamp())
    raise TypeError(f"Unsupported timestamp type: {type(value)!r}")

Then replace:

expires_at = int(row["expires_at"].timestamp()) if row.get("expires_at") else None
last_active_at = int(row["last_active_at"].timestamp()) if row.get("last_active_at") else None

with:

expires_at = to_epoch_seconds(row.get("expires_at"))
last_active_at = to_epoch_seconds(row.get("last_active_at"))

in both create_vector_store and list_vector_stores.

Environment

• Reproduced against a local Docker build of main branch, Postgres 18 + pgvector, prisma-client-py generator.