atlas-pca-haystack

Haystack guard for Proof-Carrying Authority (PCA): make every Haystack 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 Haystack 2.31.0 (ToolInvoker, Agent) and 3.3.0 (Agent; 3.x has no ToolInvoker). It covers real Tool objects through a real ToolInvoker (2.x) and Agent (2.x and 3.x), including guard_tool_invoker in a real Pipeline, thread-pool dispatch, and async tools. 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-haystack

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

Use

Entry points: pca_tool / guard_tool_invoker / guard_tools.

from atlas_pca_haystack import pca_tool

See the module docstrings in atlas_pca_haystack 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