atlas-pca-google-adk

Google ADK guard for Proof-Carrying Authority (PCA): make every Google ADK tool call proof-carrying and policy-gated. A tool only runs when the agent carries a valid, in-plan, resource-correct proof for exactly that action. The adapter delegates all verification to atlas-pca and reimplements no cryptography.

Status: 0.4.0, unaudited.

What is tested

The default test suite runs without the framework, against the shared conformance proofs. A second suite, make test-real (needs the framework installed), runs against the real framework and is pinned to Google ADK 2.11.0. It covers a real LlmAgent run through a real Runner with a scripted offline model: proofs in session state, FunctionTool wrapping, before_tool_callback allow/deny (tampered proof, wrong audience), and the denied-tool path. Each denial test checks that the tool body never ran, and checks the refusal reason wherever the framework surfaces it.

Not covered: other framework versions (only the pinned one is exercised), live model providers (the models are scripted and offline), and any property of the underlying atlas-pca verifier beyond what it already documents. This package has not been independently audited.

Install

pip install atlas-pca-google-adk

This installs atlas-pca>=0.4.0,<0.5 as a dependency.

Use

Entry points: pca_tool / pca_before_tool_callback.

from atlas_pca_google_adk import pca_tool

See the module docstrings in atlas_pca_google_adk for the full API, and the PCA specification for the model. The verifier applies the full check order, including grant_ref_bound (the signed grant_ref must equal the root capability id), as of atlas-pca 0.2.0.

Links

• Source: https://github.com/Atlas-Authorization/pca-python
• Specification and docs: https://github.com/Atlas-Authorization/pca

License: MIT