The tool is the job

Agents call tools to finish jobs. HTTP still needs resource routes. Those are different grains of the same functions, not two APIs.

Write the ZIO functions. Bind fine-grained Endpoints for HTTP and OpenAPI. Do not mark them .mcp. Bind one coarser Endpoint whose handler composes those functions. Mark that one with Api.job. Mcp.from lists the job. HTTP still serves the ingredients.

api
  .resource(createHold)(inventory.hold)
  .job(seatTheParty) { party =>
    for
      show          <- shows.get(party.showId)
      _             <- ZIO.fail(SeatingError.SoldOut(party.showId)).when(show.remaining < party.size)
      seats         <- inventory.holdBlock(party.showId, party.size)
      (total, code) <- pricing.quote(show, seats).zipPar(pickup.mint)
      order         <- orders.record(party, seats, total)
    yield PartySeated(order.id, seats, total, code)
  }

BoxOffice.seed.flatMap { store =>
  ZIO.fromEither(BoxOffice.mcpOf(store)).flatMap { mcp =>
    mcp.handle(BoxOffice.rpc("tools/list", obj())).map { out =>
      val json = out.get.toJson
      json.contains("seat_the_party") &&
      json.contains("get_show") &&
      json.contains("list_shows") &&
      !json.contains("create_hold")
    }
  }
}

true

BoxOffice.seed.flatMap { store =>
  BoxOffice.api(store).routes(Request.post("/parties", Body.json("""{"showId":1,"size":2}"""))).map { res =>
    res.status == Status.Created && res.body.asString.contains("P1001")
  }
}

true

An agent should not search for "create hold", then "create order", then hope a pickup code exists. It should call seat_the_party and get a PartySeated. The resource routes are for browsers, Swagger, and any client that wants the ingredients.