AgentGate vs Azure AI Content Safety (Prompt Shields)

AgentGate

An agent or its host can send each tool call to one REST endpoint, or wrap an MCP server, and get allow, deny or ask from a local classifier and a YAML policy, with an audit log and approval queue. The project is three days old, auth is off by default, and no detection accuracy is published.

Azure AI Content Safety (Prompt Shields)

Prompt Shields checks up to five retrieved documents for indirect injection, not only the user prompt. Needs an Azure subscription with a card, a resource and a region that has the feature, before the first call.

AgentGate

1. Create a session with the user's real goal first. The goal-alignment head scores every later call against it
2. Pass earlier tool results in history_override with untrusted: true for web or email content, or the injection head sees only the action
3. On ask, stop and tell the user the decision_id. Polling /v1/decisions/:id needs the dashboard key
4. Treat allow_with_checkpoint as allow and keep the checkpoint_id for an undo
5. Expect HTTP 404 with not_found for an unknown session and 401 when the owner has set an agent key

Azure AI Content Safety (Prompt Shields)

1. Send retrieved pages and tool results in the documents array of shieldPrompt, not in userPrompt, so document attacks are reported separately
2. Call text:shieldPrompt over REST with api-version=2024-09-01. The Python SDK 1.0.0 has no method for it
3. Keep each request under 10,000 characters across prompt and documents, and split long tool results
4. Create the resource in a region that lists Prompt Shields, since not every region has it
5. On F0 you get 5 requests a second. Queue checks or move to S0 before load testing