Self-hosted: Database model validation fails on missing policies/archives fields

[CodeCraftsman-Jr]

Description

The mcp-server-appwrite package (v0.8.1) depends on the appwrite Python SDK 21.0.0+, whose Database Pydantic model requires policies (List[BackupPolicy]) and archives (List[BackupArchive]) as mandatory fields. Self-hosted Appwrite instances (including the latest stable v1.9.5) do not return these Cloud-only fields in the database list response (GET /tablesdb).

Impact

The MCP server's startup validation (validate_services -> tables_db.list()) fails immediately with:

RuntimeError: Appwrite startup validation failed during the minimal startup probe.
- tables_db: Unable to parse response into DatabaseList: 6 validation errors for DatabaseList
databases.0.policies
  Field required
databases.0.archives
  Field required

This makes the MCP server completely unusable on self-hosted Appwrite instances.

Steps to Reproduce

1. Run a self-hosted Appwrite instance (tested on v1.9.0 and v1.9.5 stable)
2. Set up the MCP server with self-hosted config per docs/self-hosted.md
3. Start the MCP server -> validation fails on tables_db

Workaround

Making policies and archives fields Optional in the Database model resolves the issue. We are currently using a wrapper script that monkey-patches the model at import time.

Suggested Fix

Make the policies and archives fields in appwrite/models/database.py optional with a default of None:

policies: Optional[List[BackupPolicy]] = Field(default=None, alias='policies')
archives: Optional[List[BackupArchive]] = Field(default=None, alias='archives')

This is backward-compatible since Cloud instances always return these fields, and self-hosted instances simply omit them.

Environment

• Appwrite version: 1.9.5 stable (self-hosted)
• mcp-server-appwrite: 0.8.1
• appwrite Python SDK: 21.0.0

[JannikLohausComuneo]

Related failure mode on Appwrite Cloud — nested BackupArchive fields null (not just the top-level fields missing).

Hitting the same validate_services → tables_db.list() probe crash, but with a different root cause that the proposed fix here wouldn't cover, so flagging it for the same pass:

On Cloud (not self-hosted), archives is returned as a populated list — but for pending or failed backup archives, Appwrite Cloud returns null for size and startedAt. The appwrite-21 SDK's BackupArchive model declares size (float) and startedAt (str) as required/non-null, so validation fails with ~16 errors like:

BackupArchive.size: Input should be a valid number [input_value=None]
BackupArchive.startedAt: Input should be a valid string [input_value=None]

→ server never finishes the startup probe → client sees MCP error -32000: Connection closed.

Making Database.policies/archives Optional (the fix proposed above) won't resolve this — here archives is present and non-null; it's the items inside that carry nulls. The nested BackupArchive.size/startedAt (and likely the BackupPolicy fields too) need to be Optional[...] = None as well, or the probe should not eagerly validate backup archives.

Workaround (same family): pin mcp-server-appwrite==0.4.1 — the newest release on the pre-21 SDK (appwrite 15.x, no archives field), which starts cleanly.

Env: mcp-server-appwrite 0.8.1 · appwrite Python SDK 21.x · Appwrite Cloud.