MCP | Documentation

The mcp feature adds POST /mcp to TKeeper's public HTTP server. An agent host can discover permitted identities and authorities, read command schemas, verify signatures, and request governed signing or composition. The host holds the Keeper token and sends it with each request.

What the tools provide

Tools	Result	Permission
`identity.list`, `identity.describe_authority`	Active signing identities, authority descriptions, command JSON Schemas	`tkeeper.key.<keyId>.sign`
`utility.keeper_status`	Sealed and ready state	`tkeeper.system.status`
`utility.get_public_key`	Public key for an identity	`tkeeper.key.<keyId>.public`
`utility.verify_signature`	Cryptographic command verification	`tkeeper.key.<keyId>.verify`
`action.sign`, `action.compose`	Signature or composed result	`tkeeper.key.<keyId>.sign`

tools/list shows tools available to the caller. Each tool call checks permission again for its target key. identity.describe_authority exposes the input schema; the attached authority and policy decide whether a submitted command may be signed.

Connect an agent host

Build Keeper with mcp and the authority features the host needs. mcp is an explicit build selector, including when keeper.features=all is selected:
```
./gradlew :build -Pkeeper.features=mcp,digital-assets,agentic-payments -Pkeeper.platforms=ecc
```
For local developer authentication, also select auth-dev and follow the single-node setup.
Run Keeper with its normal public server and authentication configuration. Create a key with an authority before expecting it in identity.list. MCP uses the same public port; there is no separate MCP process.
Configure the agent host for Streamable HTTP at https://<keeper-public-host>/mcp. It must support MCP version 2026-07-28, the server/discover, tools/list, and tools/call methods, and custom request headers:

Authentication mode Request header

Production JWT X-JWT-TOKEN: <raw-jwt>

Local auth-dev X-DEV-TOKEN: <dev-token>

Send the token from the host on every request. Browser requests with an Origin header are rejected, so connect from a server-side host. Keeper accepts HTTP POST and returns JSON.

Authentication mode	Request header
Production JWT	`X-JWT-TOKEN: <raw-jwt>`
Local `auth-dev`	`X-DEV-TOKEN: <dev-token>`

Check the connection

With a JWT for the agent host, list the available tools:

curl -sS 'https://<keeper-public-host>/mcp' \
  -H 'X-JWT-TOKEN: <raw-jwt>' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/list' \
  --data '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientCapabilities":{}}}}'

For tools/call, set Mcp-Method: tools/call, set Mcp-Name to the tool name, and supply the same name plus arguments in params. The response places a tool's data in result.structuredContent; tool failures set result.isError: true. Discovery and tool lists have ttlMs: 0 and cacheScope: private, so refresh them after permission or authority changes.

Govern signing

Attach a digest-pinned authority to each signing key and grant the host tkeeper.key.<keyId>.sign only for the keys it may use. action.sign and action.compose run the regular policy, approval, audit, and signing pipeline. The system that performs the action must verify the returned proof and enforce freshness or replay rules.

For AI has a complete governed action and tools/call request. See agentic payment authorities and digital asset authorities for command examples. The feature reference lists each tool.