feat: add return type hints to API endpoint functions

[allenjoseph05]

Description

Adds missing return type hints to API endpoint functions as specified in issue #2043.

Changes Made

• Added return type hints to 7 functions across 5 files:
  • classify() in cognee/modules/ingestion/classify.py → Union[TextData, BinaryData, S3BinaryData]
  • delete(), delete_single_document(), delete_document_subgraph() in cognee/api/v1/delete/delete.py → dict
  • update() in cognee/api/v1/update/update.py → Any
  • visualization_server() in cognee/api/v1/visualize/start_visualization_server.py → callable
  • visualize_graph() in cognee/api/v1/visualize/visualize.py → Any
• Note: ui.py functions already had return type hints

Testing

• Verified all functions have type hints using verification script
• Code follows Python typing conventions
• Pre-commit hooks passed (formatting applied)
• All existing functionality preserved

Related Issue

Fixes #2043

Summary by CodeRabbit

• Refactor
  • Enhanced code quality with improved type annotations across API functions for better maintainability and code clarity.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[pull-checklist]

Please make sure all the checkboxes are checked:

• I have tested these changes locally.
• I have reviewed the code changes.
• I have added end-to-end and unit tests (if applicable).
• I have updated the documentation and README.md file (if necessary).
• I have removed unnecessary code and debug statements.
• PR title is clear and follows the convention.
• I have tagged reviewers or team members for feedback.

[coderabbitai]

Walkthrough

Add return type annotations to five API endpoint and utility functions across delete, update, visualize, and ingestion modules to improve type safety and IDE autocompletion. Functions now explicitly declare return types as dict, Any, callable, or Union types matching their actual return values.

Changes

Cohort / File(s)	Summary
Delete API Functions cognee/api/v1/delete/delete.py	Added return type annotations (-> dict) to three public async functions: delete(), delete_single_document(), and delete_document_subgraph().
Update API Function cognee/api/v1/update/update.py	Added return type annotation (-> Any) to the update() function.
Visualize API Functions cognee/api/v1/visualize/start_visualization_server.py, cognee/api/v1/visualize/visualize.py	Added return type annotations to visualization_server() (-> callable) and visualize_graph() (-> Any). Added import for Any from typing module.
Ingestion Classify Function cognee/modules/ingestion/classify.py	Added return type annotation (-> Union[TextData, BinaryData, S3BinaryData]) to the classify() function.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Suggested labels

run-checks

Suggested reviewers

• pazone
• hajdul88
• siillee

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: adding return type hints to API endpoint functions, which matches the changeset.
Description check	✅ Passed	The description adequately covers the changes, lists affected functions with their return types, documents testing performed, and links to the related issue.
Linked Issues check	✅ Passed	The PR successfully addresses all coding requirements from issue #2043: type hints added to all 7 specified functions with appropriate return types that match actual return values.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to adding return type hints to the functions specified in issue #2043; no unrelated modifications detected.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[github-actions]

Hello @allenjoseph05, thank you for submitting a PR! We will respond as soon as possible.

[Vasilije1990]

@allenjoseph05 please check CONTRIBUTING.md and open a PR against dev branch + upload the screenshot of tests passing locally

[allenjoseph05]

Hi @Vasilije1990,

I've completed the type hint additions for all functions listed in the issue. However, I wanted to address the testing requirement mentioned in CONTRIBUTING.md.

I attempted to run cognee/tests/test_library.py locally but encountered OpenAI API quota limitations (my account has insufficient credits). Since this is a type annotations-only change with zero functional modifications, I wanted to explain my testing approach:

What I verified locally:
Pre-commit hooks (ruff format, ruff check) - all passed
Python syntax validation - all files parse correctly
Import verification - all modified modules import successfully
Type annotations are syntactically correct

[Vasilije1990]

@allenjoseph05 understood. We will merge it then, but please open against dev branch, not main

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