AFFIXIO
MCP verification
MCP agent verification
MCP servers expose powerful tools. Gate those tools on signed agent eligibility before execution. AffixIO MCP verification connector patterns show how to call verify from Claude, Cursor, and compatible clients.
Definition
MCP agent verification is a pre-execution policy gate that returns signed allow or deny before an MCP tool runs.
Field note. MCP tool calls without upstream verify are indistinguishable from shadow automation in your audit trail.
Connector pattern
Place AffixIO verify in the MCP path before privileged tools. On deny, do not execute. On allow, proceed and attach Merkle metadata to the tool trace.
Documentation lives at the MCP verification connector page and MCP connect docs.
What to gate first
Start with tools that move money, export data, or change production state. Lower-risk read tools can follow once the pattern is stable.
Combine with know-your-agent eligibility so the caller is in scope before the tool policy is evaluated.
Boundary hooks for MCP agent gates
Wire AffixIO verify immediately before the boundary where MCP agent gates applies: checkout authorisation, MCP tool invocation, age gate, or offline scan. Issue proofs when policy is satisfied. Present at the edge. Gate on signed allow or deny.
Train support on deny retrieval: Merkle ref lookup should not require engineering access. Document which circuit version was active when the proof was issued.
Evidence hole
Tools without a gate
MCP makes it easy to wire file, payment, and data tools into agents. Without verification, every connected tool inherits the agent's ambient trust.
Ambient privilege
Once connected, tools may run without per-call policy checks.
Prompt-only controls
Instructions are not cryptographic evidence and fail under adversarial input.
Weak incident evidence
After a bad tool call, logs show the call, not a signed permission decision.
Agent card check
Verify MCP agents before tool execution, not after logs
MCP agents that invoke tools on shared secrets fail when any compromised host can impersonate another. Issue short-lived proofs at policy satisfaction and verify at the MCP boundary.
Install connector patterns
Follow MCP connect docs.
Classify tools by risk
Gate high-risk tools first.
Verify pre-exec
Allow or deny before tool body runs.
Retain audit refs
Attach Merkle metadata to traces.
Production checks
Readiness checks for MCP agent gates
- Inventory MCP tools and their blast radius.
- Wire verify before privileged tools.
- Define deny behaviour in the client UX.
- Keep prompts out of the verifier by default.
- Test with sandbox proofs before production keys.
Merchant FAQ
Questions on MCP agent gates
Where is the connector documented?
See /mcp-verification-connector/ and /docs/mcp-connect.
Does AffixIO store prompts?
No. By default the verifier receives allow or deny and proof metadata, not conversation content.
Can we gate only some tools?
Yes. Start with high-risk tools.
Which clients?
Claude, Cursor, and MCP-compatible clients using the connector patterns.
Continue here
Pages that support MCP agent gates
AI agents
More AI agent briefs
Test MCP agent gates in sandbox
Verify agent proofs on live MCP connectors, then map the same gate to production tool invocation.