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Tool discovery and review

Aethis can only govern a tool it understands. Tool discovery is how Aethis learns what an MCP server offers, and review is how you decide whether a new or changed tool may be used.

Discovery

Section titled “Discovery”

When you select Refresh tools on a Connection, Aethis asks the MCP server for its tool catalogue and records each tool’s definition: its name, description and parameters. Each definition gets a capability fingerprint, so Aethis can tell later whether the tool it is being asked to call is the same tool you reviewed.

Discovery requests, health checks and pings are not governed actions and don’t count against your plan.

Why changes pause execution

Section titled “Why changes pause execution”

An MCP server can change a tool’s definition at any time. A refund tool whose amount switches from whole currency units to cents, for example, would make an approved “SGD 500” limit mean something very different.

So when a refresh returns a definition that differs from the one you accepted, Aethis:

  1. marks the tool Changed and the Connection Review changes
  2. sets the Connection’s execution boundary to Frozen, so calls through it don’t run
  3. opens a Capability Drift alert for the affected Agents

Nothing runs through the changed Connection until someone reviews the catalogue.

Review

Section titled “Review”

The Connection’s Tools section shows the previously accepted definition next to the new one. The review decision applies to all pending changes in the Connection:

  • Accept catalogue trusts the new definitions and lifts the pause.
  • Reject changes records that you didn’t accept them and keeps the Connection Frozen. Fix the server, then select Refresh tools and review again.

Acknowledging the Capability Drift alert doesn’t resume execution. Only the catalogue review does, and the alert can’t be resolved until the review is done.

Tool meaning

Section titled “Tool meaning”

Some tools need more than a matching definition before policy can evaluate them. A refund tool’s amount needs a confirmed unit and currency, for example. When a catalogue is current but a tool’s meaning is still unresolved, the Connection shows Review tool meaning, and the tool’s access on an Agent shows Unresolved until it is reviewed.

Tool trust states

Section titled “Tool trust states”

A discovered tool is Trusted, New, Changed, Removed or Stale. See Statuses.

To do the review, follow Review tool changes.