/ Enterprise MCP Gateway

Policy-Filtered Discovery

Agents shouldn't see a broad catalog first and get denied later.

With policy-filtered discovery, the tool list an agent sees is already shaped by who it is, where it runs, and what policy allows — so the first view is already governed.

12 chapters · ~4 min read

01

Context Before Catalog

User, agent, surface, and environment context arrive before the catalog opens.

Context Before Catalog

Why it mattersTool visibility depends on who is asking and where they are acting.

02

Approved Does Not Mean Visible

A tool can be approved in the registry and still hidden from a specific agent.

Approved Does Not Mean Visible

Why it mattersRegistry approval and runtime visibility are different controls.

03

Policy Lens

Group, agent, client, delegator, and rule context focus the visible list.

Policy Lens

Why it mattersDiscovery needs policy evaluation, not a static catalog dump.

04

Discovery Gate

tools/list passes through session and policy checks, with no bypass path.

Discovery Gate

Why it mattersUnauthorized tools should not leak through discovery before call-time denial.

05

Allowed Tools Tray

The agent receives only the tools that are visible, allowed, low-risk enough, and from the right source.

Allowed Tools Tray

Why it mattersA small allowed list makes agent behavior easier to reason about.

06

Hidden Means Hidden

Hidden tools are not advertised, hinted, or credentialed.

Hidden Means Hidden

Why it mattersDiscovery is a prevention layer, not just a convenience layer.

07

Same Agent, Different Surface

The same agent can see different lists in an IDE, support bot, or production app.

Same Agent Different Surface

Why it mattersClient surface changes risk and intent.

08

Environment Boundary

Dev and production discovery stay separated by environment.

Environment Boundary

Why it mattersProduction tools should not appear because a dev context happened to work.

09

Risk And Credential Mode

Risk tier and credential mode affect which tools become visible.

Risk And Credential Mode

Why it mattersVisibility should account for how the downstream call would be authorized.

10

Session State

Active, expired, and step-up states can require a refreshed list.

Session State

Why it mattersA stale discovery list can become an authorization bug.

11

Delegated Authority

Delegated authority narrows the visible list through policy.

Delegated Authority

Why it mattersActing for someone else should not expand capability by accident.

12

Discovery Evidence

Discovery evidence records policy version, actor context, visible list, and audit receipt.

Discovery Evidence

Why it mattersTeams need to explain why the agent saw a tool before it called it.

Discovery control

Make your agent's first view already governed

We are looking for teams who want policy-filtered tool discovery for real agent surfaces.

Start with one agent, one surface, and one tool family. We will define the allowed list, hide what policy excludes, run discovery through the gateway, and review the evidence together.

The goal is to make the agent's first view already governed.

Talk to our team
Make your agent's first view already governed