feat: galileo adk to natively support custom retriever tools

[savula15]

User description

Shortcut:
https://app.shortcut.com/galileo/story/55769/galileo-adk-to-support-retriever-tools

Tests:

• Unit Tests Added
• E2E Test Added (if it's a user-facing feature, or fixing a bug)

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Generated description

Below is a concise technical summary of the changes proposed in this PR:
Introduces native support for custom retriever tools by providing a @galileo_retriever decorator and enhanced detection logic within the GalileoObserver. These changes allow the ADK to distinguish between standard tools and retrievers, enabling RAG-specific quality metrics and improved trace visualization.

Topic	Details
Span & Trace Logic	Update SpanManager and TraceBuilder to handle 'retriever' node types and correctly format document outputs for RAG metrics. Modified files (5) galileo-adk/pyproject.toml galileo-adk/src/galileo_adk/span_manager.py galileo-adk/src/galileo_adk/trace_builder.py galileo-adk/tests/test_span_manager.py galileo-adk/tests/test_trace_builder.py Latest Contributors(2) User Commit Date ci@rungalileo.io chore-release-galileo-... February 11, 2026 sankar@galileo.ai feat-add-galileo-adk-i... February 10, 2026
Retriever Detection	Implement the @galileo_retriever decorator and update GalileoObserver to detect custom and built-in ADK retrieval tools. Modified files (5) galileo-adk/README.md galileo-adk/src/galileo_adk/__init__.py galileo-adk/src/galileo_adk/decorator.py galileo-adk/src/galileo_adk/observer.py galileo-adk/tests/test_retriever.py Latest Contributors(2) User Commit Date ci@rungalileo.io chore-release-galileo-... February 11, 2026 sankar@galileo.ai feat-add-galileo-adk-i... February 10, 2026

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[codecov]

Codecov Report

❌ Patch coverage is 93.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.55%. Comparing base (d1f987a) to head (1693801).

Files with missing lines	Patch %	Lines
galileo-adk/src/galileo_adk/observer.py	84.61%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #482      +/-   ##
==========================================
+ Coverage   81.85%   82.55%   +0.70%     
==========================================
  Files          96      106      +10     
  Lines        9164    10269    +1105     
==========================================
+ Hits         7501     8478     +977     
- Misses       1663     1791     +128     

Flag	Coverage Δ
galileo-adk	88.59% <93.33%> (?)

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[baz-reviewer]

TraceBuilder.add_retriever_span repeats the same convert_to_documents + kwargs construction that already lives in GalileoLogger.add_retriever_span (src/galileo/logger/logger.py:1167‑1185), so we now maintain two copies of the retriever-span argument prep. Can we add a helper such as def build_retriever_span_kwargs(input, output, redacted_input=None, redacted_output=None, name=None, duration_ns=None, created_at=None, metadata=None, tags=None, status_code=None, step_number=None) -> dict[str, Any] (maybe in galileo.utils.retrievers), have both callers use it to get documents/redacted_documents + the common dict, and then pass the shared kwargs to their respective super().add_retriever_span + post-processing?

_{Finding type: Code Dedup and Conventions}

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