drug-discovery-prompts/upstream/K-Dense-AI-scientific-agent-skills/skills/pyzotero/references/error-handling.md

title, task, lineage_type, upstream_source, upstream_sha, imported_at, prompt_class, upstream_changes, author, validated

title	task	lineage_type	upstream_source	upstream_sha	imported_at	prompt_class	upstream_changes	author	validated
Error Handling		import	https://github.com/K-Dense-AI/scientific-agent-skills/blob/9c9bd2e9/skills/pyzotero/references/error-handling.md	9c9bd2e9	2026-06-27	prompt	accepted	upstream	false

Error Handling

Exception Types

Pyzotero raises ZoteroError subclasses for API errors. Import from pyzotero.zotero_errors:

from pyzotero import zotero_errors

Common exceptions:

Exception	Cause
UserNotAuthorised	Invalid or missing API key
HTTPError	Generic HTTP error
ParamNotPassed	Required parameter missing
CallDoesNotExist	Invalid API method for library type
ResourceNotFound	Item/collection key not found
Conflict	Version conflict (optimistic locking)
PreConditionFailed	If-Unmodified-Since-Version check failed
TooManyItems	Batch exceeds 50-item limit
TooManyRequests	API rate limit exceeded
InvalidItemFields	Item dict contains unknown fields

Basic Error Handling

from pyzotero import Zotero
from pyzotero import zotero_errors
import os

zot = Zotero(
    os.environ['ZOTERO_LIBRARY_ID'],
    os.environ.get('ZOTERO_LIBRARY_TYPE', 'user'),
    os.environ['ZOTERO_API_KEY'],
)

try:
    item = zot.item('BADKEY')
except zotero_errors.ResourceNotFound:
    print('Item not found')
except zotero_errors.UserNotAuthorised:
    print('Invalid API key')
except Exception as e:
    print(f'Unexpected error: {e}')
    if hasattr(e, '__cause__'):
        print(f'Caused by: {e.__cause__}')

Version Conflict Handling

try:
    zot.update_item(item)
except zotero_errors.PreConditionFailed:
    # Item was modified since you retrieved it — re-fetch and retry
    fresh_item = zot.item(item['data']['key'])
    fresh_item['data']['title'] = new_title
    zot.update_item(fresh_item)

Checking for Invalid Fields

from pyzotero import zotero_errors

template = zot.item_template('journalArticle')
template['badField'] = 'bad value'

try:
    zot.check_items([template])
except zotero_errors.InvalidItemFields as e:
    print(f'Invalid fields: {e}')
    # Fix fields before calling create_items

Rate Limiting

The Zotero API rate-limits requests. If you receive TooManyRequests:

import time
from pyzotero import zotero_errors

def safe_request(func, *args, **kwargs):
    retries = 3
    for attempt in range(retries):
        try:
            return func(*args, **kwargs)
        except zotero_errors.TooManyRequests:
            wait = 2 ** attempt
            print(f'Rate limited, waiting {wait}s...')
            time.sleep(wait)
    raise RuntimeError('Max retries exceeded')

items = safe_request(zot.items, limit=100)

Accessing Underlying Error

try:
    zot.item('BADKEY')
except Exception as e:
    print(e.__cause__)    # original HTTP error
    print(e.__context__)  # exception context